HIGHLIGHTED VIDEO: WHALE FALL. When a whale dies, the story has just begun.
A beautiful video featuring amazing art married with science! Directed by Sharon Shattuck and Flora Lichtman for Sweet Fern Productions. Director of Photography: Artem Agafonov. Music by Rachel's. A video compliment to Radiolab's 'Loops' episode, in collaboration with producer Lynn Levy.
More great science videos here.
HIGHLIGHTED ADORABLE BABY ANIMALS VIDEO: Bear cubs make a love train.
More videos like this at: The AVM Video Thread.
ASTRONOMY: The Goldilocks zone could shrink due to tidal heating. A previously overlooked heating factor may shrink in half current estimates of the habitable zone, or Goldilocks zone, of our own Milky Way, at least when it comes to red dwarfs or "M" stars. Gravitational heating by way of tides could be a major source of internal heat. In our planetary system, the zone at which liquid water can exist goes from the inner edge of Mars's orbit to the outer edge Venus's orbit. However, for smaller, cooler stars such as red dwarfs, the liquid-water zone could be closer, the equivalent of Mercury for our solar system, or closer. But because tidal forces change drastically with the distance between a planet and its star, closer orbits effect massive tidal forces. Tidal forces cause the planet to stretch and contract, and those forces produce a massive amount of heating. Slight deviations from a perfectly circular orbit produce substantial tidal heating. According to calculations made by Rory Barnes, an astrobiologist at the University of Washington in Seattle, many of these planets could easily have already undergone sufficient heat to lose all of its water through evaporation. These planets would be, according to Barnes, "permanently sterilized." The findings are theoretical for now, but it may be an important consideration when trying to decide whether an Earth-like planet circling a red dwarf is our win or more like tidal Venus.
HUMAN EVOLUTION: The gene duplication that changed our brains. Extra copies of a gene involved in brain development and making neuronal connections, called SRGAP2, may have allowed our evolving brains to make more neural connections at a greater distance, perhaps shaping our brains into what they are now. The gene duplications occurred ~2-3 million years ago, coincident with the time when hominid brains got a lot larger. As you can see in the figure, representing chromosome 1 pairs, probed to detect SRGAP2 sequences, chimpanzees and orangutans only have just 2 alleles of the SRGAP2 gene, in chromosome one, while humans have additional copies. SRGAP2 is highly conserved through mammalian evolution, and the human lineage is the only one so far to have duplications. One of these copies, called SRGAP2C is a truncated version of the parental copy, and it competes with the "original" ancestral gene. Both copies are expressed in the developing brains of human infants. The competition between the two forms of SRGAP2 probably allow for neurons to develop more connections. When scientists introduced the SRGAP2C form in mouse embryos, the mice developed more spiny projections and they developed longer stalks and larger heads. Now correlation is not causation, but the role of this genes, the fact that the extra copies are unique to humans, and the timing at which it appeared, when our ancestors' brains grew larger and they started to use make tools, is very suggestive of a role of this duplication in brain development in the common ancestor of the Homo lineage. Gene duplications are crucial in evolution because the presence of extra copies allows for random mutations to accumulate in the copies, without damaging the function of the original gene, especially in this case, because the function of this gene is crucial to brain development.
PALEONTOLOGY: Dwarf mammoths in Crete. Here is another wonderful case of "island dwarfism", an evolutionary phenomenon occurring in isolated ecosystems where resources may be scarce and small body sizes could thus be favored. Paleontologists have found the fossil remains of a mammoth that as an adult, was no bigger than a modern newborn elephant. The new species is called Mammuthus creticus. The dwarf mammal co-existed with a dwarf elephant in Crete. The fossils consists of several molar teeth, which have a unique enamel signature pattern of ridges and loops seen only in mammoths. This species is not the first example of island-dwelling smaller mammoths, but it is the tiniest so far. Smaller-sized mammoths were found on Wrangel Island off the coast of northeastern Siberia and on the Channel Islands off California.
NEUROSCIENCE: Our brains can predict ad effectiveness better than we can. I know the title of the discussion seems a bit of mystifying, since a few of us could think our brains are us. Well, not really, our brains and minds do a lot of stuff we are absolutely not aware of. It turns out that brain activity in the medial prefrontal cortex (MPFC) is a better predictor of how effective an ad will be, than the opinions of the brain's owners. Social neuroscientists at UCLA carried out a very interesting experiment. They measured fMRI activity in 30 heavy smokers who had expressed a desire to quit, while they watched 3 different ads campaigns that aimed at getting smokers to call the National Cancer Institute's quit hotline. They asked these 30 people to rate the ads in terms of effectiveness. They picked an ad featuring a woman so desperate for a nicotine fix, that she imagines jumping out of a window to get a lit cigarette a passerby threw away, as the most effective at getting people to call the hotline. Then they favored a funny ad about a man learning to drink coffee without a cigarette, and third, or least effective, a humorous ad with finger puppets. Interestingly, experts in marketing for health care came up with the same rankings. But the neural responses of participants told a different story. The finger puppet ad provoked the most MPFC activity, followed by the jumping woman, and then the coffee drinker. Call volumes to the NCI hotline agreed with the order predicted by the MPFC activity in the smokers brain, and not by their opinions as to which ad would be most effective: there was a 32 fold increase after the finger puppets, a ~12 fold increase after the jumping woman ad campaign was aired, and only 2.3-fold increased after the coffee drinker ad. A sample of 30 people is a bit small to draw huge conclusions, but if this holds in larger groups, it's absolutely fascinating. And the marketers will really have us for breakfast.
ANIMAL BEHAVIOR: Humpback whales intervene in orca attack on gray whale calf. A fascinating behavior of possible inter-species altruism was observed in Monterrey Bay (California): two humpback whales appeared to obstruct a pack of killer whales that were attacking a grey whale calf. The mother grey whale tried to save her calf by floating it on her back, while the humpbacks splashed, produced bubbles, and appeared to attempt to come between the orcas and the grey whale mother and baby pair. There were nine orcas, and eventually they succeeded in killing the exhausted calf. Three more humpbacks joined and followed the orcas, blowing, hitting their tails against the surface, rolling, and raising their heads, as if wanting to interfere with the orcas feasting on the blubber of the dead grey whale calf.
Science bits and news from other sites:
A film project, called 94 elements, will highlight the human stories behind the chemical elements and as well as the rate at which we are depleting them. While our human bodies are mostly made from just six elements, we exploit many more of them, basically the whole periodic table. Our economies and sometimes our cultures depend on the exploitation of chemical elements. The 94 Elements project will do a series of films, each centered around one element and it’s relationship to humans. Two have been produced already: Oxygen, by Bafta winner Marc Isaacs and Gadolinium, by Sundance-winner Nino Kirtadze. The main idea is to draw attention to all the stuff we make and consume, and what it entails in terms of resources. Helium, for example, is the second most abundant element in the universe, but is in increasingly short supply in our own planet. Indium (used on computer screens, could run out in around 10 years. Silver could have only 30 years left. We are pretty good at recycling some “old” elements, such as aluminum and copper (80% of all copper ever mined is still in use today), but not that good with elements that are of more recent discovery, or of exciting new uses, such as cell phones. Sadly, most cell phones will end up in a landfill with no recycling of its chemical elements. The project seems to me very interesting and very timely. I’m looking forward to seeing some of these films.
Japan switches off its last nuclear reactor. This week has been very significant for Japan and the future of its nuclear power. Hokkaido Electric Power Company shut down Japan’s last operating nuclear reactor. The reactions are mixed: a sigh of relief from anti-nuclear activists, but worry from economic sectors, who worry that Japan, will not be able to handle higher energy costs, especially in light of a very strong yen. Two years ago, Japan introduced plans to reduce carbon emissions by 25% by 2020, based on the addition of 14 state-of-the-art, high-powered nuclear reactors to its old arsenal of 54 existing, aging reactors. Then came the earthquake, tsunami, and the Fukushima crisis. Four of the 54 reactors were destroyed, releasing some 8 x 1017 becquerels of radioactivity into the environment. Nobody in Japan seems to think now that any more reactors should be built. The 50 working reactors are now all shut down for maintenance. After Fukushima, they face more stringent safety tests and, more opposition from local residents. It is not clear when the reactors will be turned on again. Business elites say that it should be soon, if the economy is to avoid severe damage. The test will be happening soon, since summer is arriving. The summer of 2011 was unusually cool, and residents all rallied after the crisis to cut consumption and save energy. But will happen when August rolls in and people get hot, sweaty, and have to sit in the dark? The power industry is actually hoping for a hot summer so that they can convince residents to bring the reactors back online.
Your willingness to work hard is affected by dopamine in your brain. Are you a hard working person? Are you motivated by the perspective of higher earnings? A new brain imaging study at Vanderbilt University suggests that the willingness to work hard to earn money is strongly influenced by our brain chemistry. Using a brain mapping technique called positron emission tomography (PET scan, researchers determined that three specific areas of the brain are implicated: the striatum and the ventromedial prefrontal cortex (VMPFC), already implicated in reward and motivation, and the anterior insula, which was surprising. More dopamine in the insula is associated with a reduced desire to work, even when it means earning less money, while higher dopamine in the other two areas is associated with an increased willingness to work hard to earn more. This is important because the fact that dopamine can have opposing effects in different parts of the brain complicates the use of psychotropic medications that affect dopamine levels (such as those used to treat ADHD, depression and schizophrenia). Up until now, the general assumption was that these dopaminergic drugs have the same effect throughout the brain. The study was small, using 25 male and female healthy volunteers, in equal proportion 18 to 29 years old. They were asked to perform an easy or harder button-pushing task. The easy task earned them $1 while the hard tasks up to $4. Each task lasted for ~ 30 seconds and volunteers had to “work” for 20 minutes. Of course, a 20 minute snippet of behavior cannot be assumed to correlate to long term achievement but it does measure a variable trait, which is the willingness to make an effort for monetary rewards. The research is part of a larger project that aims to find for objective measures for depression and other psychological disorders, where there is lack of motivation or reduced motivation. An objective test would help pinpoint the underlying conditions.
Chickens, relax: your sex chromosomes are here to stay. Sex chromosomes have been shrinking throughout millions of years, and a lot of not-so-good popular science has been written on the presumed demised of the male Y chromosome, since the Y chromosome DNA does not recombine with its partner, the X chromosome. Several scientists have however dismissed the concerns about its possible “extinction.” In mammals, males are the heterogametic sex, meaning they produce sperm with either an X or a Y chromosome; females make eggs with an X chromosome, therefore, males determine the sex of the offspring. But in birds, in this case chickens, females are the heterogametic sex, they produce eggs with either a W (the equivalent of the Y), or a Z chromosome (the counterpart to the mammalian X chromosome). Hens, not roosters, determine the sex of the offspring). The W chromosome has also shrunk and also cannot recombine, just like the mammalian Y chromosome. Professor Judith Mank, from the UCL Department of Genetics, Evolution and Environment, and her team have compared DNA regions on the W chromosome in different breeds of chickens, that have different fertility rates (measured as how many eggs they lay. They studied two breeds, the Minorca and Leghorn, which lay > 250 eggs/year, two breeds selected for male traits (fighting and plumage; the Yokohama and Old English Game), and also red jungle fowl, a wild ancestor of chickens. The layer breeds had elevated expression of all the genes in the W chromosome; these determined fertility. The fighting and plumage breeds, where females were not selected, had lost expression of some W chromosome genes. In other words, the W chromosome is responsible for fertility rates and can quickly respond to selective pressure, even if it cannot recombine. Professor Mank concluded that both the Y and W chromosomes are very important in fertility, and this suggests that both the Y and the W chromosomes are going to stick around for a long time.
Dolphins are dying by the thousands on the coast of Perú. Scientists, veterinarians and officials in Perú are struggling to understand why thousands of dolphins and seabirds have died over the last few months. Peruvian fishermen say that 3,000 or more dolphins have died off the country’s northern coast since late last year, though the government puts the figure at <900. The cause of these massive deaths could be from many possible factors, including infectious disease, parasites, starvation, pollution (including noise pollution), injuries and algal blooms that release huge amounts of biotoxins. Seismic testing for oil and natural gas with high-tech sonar equipment is thought to have contributed to some of the deaths. A veterinarian noted hemorrhagic lesions in the middle including the acoustic chamber, fractures in the periotic bones, bubbles in blood filling liver and kidneys, lesion in the lungs compatible with pulmonary emphysema, sponge-like liver. These are compatible with acoustic impact and decompression syndrome. Houston's BPZ Energy has exclusive license contracts over ~2.2 million acres in four blocks in northwest Perú, including offshore, where they are undertaking seismic testing. BPZ Energy operations are located 500 km north of the area where dolphin deaths are being reported. However, Peruvian officials are saying that the deaths are due to an outbreak of morbillivirus, a virus in the same family that causes measles and canine distemper. Frances Gulland, a senior scientist and veterinary care expert at the Marine Mammal Center in Sausalito, California, has said that morbillivirus could be a “possible” cause but she would need to see data. The public tends to think that there is a “CSI Dolphin” type of scenario where the causes are quickly found, but it is in really very hard to determine what causes the deaths of marine mammals. In Peru, many of the dolphins appeared to have died in open water before being washed ashore, so they were already damaged before the scientists could take a look at them.