Tomorrow is the first anniversary of our social networking site. I want to personally thank the many members who have contributed and continue to contribute to the science discussions. I also want to especially thank Michel, who suggested the major improvement of including visuals in the blog, and for designing such beautifully artistic covers for the Main Page. Science and art are perfect partners, because they both stimulate our thinking and they both are capable of producing such great pleasures for our minds and our senses.
For those who are new to our site, I divide the blog in two parts: the Science at Atheist Universe, which includes selections of what other members and myself post in our site, and also Science Bits and News from Our Sites, in which I include selected information from various science-related sites that I think are worth highlighting.
Science at Atheist Universe
VIDEO OF THE WEEK: Cranes flying over Venice
Filmed by the BBC. Unbelievable beauty, that of the birds, as well as the magnificent water world and architectural beauty of Venice, one of the most unique and beautiful cities in the world.
More remarkable videos at the AVM video Thread here
Two noteworthy ASTRONOMY discussions:
Young Stars Flicker Amidst Clouds of Gas and Dust. Several stars in the earliest stages of evolution were detected in the Orion Nebula amid clouds of dust and gas. The colorful young stars, called “protostars”, were detected thanks to the European Space Agency's Herschel Space Observatory and NASA's Spitzer Space Telescope. The stars are rapidly heating up and cooling down, as all newly formed do in their way to star “adulthood.” All stars form when clumps of gas and dust collapse, and after accumulating enough material (a process that takes several hundred thousand years), nuclear fusion is triggered and they become full-fledged stars. The Herschel telescope is very sensitive and the newly gathered data is allowing astronomers to study star formation in great detail
Newly discovered asteroid is headed toward Earth, ETA 2040. A big asteroid, 2011 AG5 (460 feet, or 140 meters wide) could come very close to Earth and result in a collision on February 5th, 2040. Since the chance of impacting the Earth could be 1 in 625, some scientists think this big chunk of rock is a real threat and are keeping a close eye on it. Some researchers even want to initiate a discussion on how to deflect it. At this point, the impact probability is not precise, and further observation of its orbit is needed. In 2023, the asteroid may pass through a keyhole, a region in space where the orbit of an object may be altered due to gravitational effects, and possibly placing it onto a collision path with Earth. Processing additional observations in the 2013-2016 time period, will be important for determining the impact probability for 2011 AG5. If the impact threat of the asteroid persists beyond its 2013 apparition, there would be two options to deflect the big rock: an expensive multi-kinetic impactor or a nuclear explosive. NASA Administrator Charles Bolden said that 2011 AG5 is "high on NASA’s list of NEOs (Hear-Earth Objects) to monitor for impact hazard potential." However, since the the asteroid makes an apparition in 2015, 7 years before the close keyhole passage in 2023, there would be more that sufficient time to take action.
PHYSICS: Evidence for Antimatter Anomaly Mounts. Why does the universe exist? According to theoretical physicists, if the Big Bang had generated the same amount of antimatter as of matter, the universe would not have survived. We know the universe survived, so physicists are looking for explanations, basically searching an asymmetry between matter and antimatter, technically known as charge-parity (CP) violation. Although there have been some hints that this "violation" exists, there is still no conclusive evidence, because the measurements could represent statistical flukes. New data from the Collider Detector at Fermilab (CDF) are still not conclusive evidence, but they bring the chances of a fluke to 1 in 10,000. To study CP violation, physicists look for differences in the rate of decay between particles and their corresponding antiparticles. The higher difference in decay, the greater the chances that it is real. Both the Large Hadron Collider (LHCb) and the CDF are searching for differences in rates of decay. Last year, the LHCb team reported that decay rates that differed by 0.8%, but the statistical significance was not great, allowing for a 1 in 100 chance (3 sigma) that the observation was a random blip in the data. The latest CDF measurements report a CP violation of 0.6%, at 2.7 sigma). The two results combined bring sigma to 3.8, which is close to 1 in 10,000 chance that it is a statistical fluke. The holy grail is 5 sigma, which is 1 in 1,000,000 chance of being random instead of real. When the rest of the LHCb data is analyzed by the end of 2012, we will have a better idea of whether 5 sigma has bern approached or achieved.
Two great posts in NEUROSCIENCE:
Can science ever explain consciousness?. I think science will be able to explain consciousness, provided that we can define it. Did you ever ask yourselves what consciousness is? Neuroscientists tend to define consciousness as the opposite of an unconscious or asleep state, in other words, as the ability to be aware, attending and alerts towards our surroundings. Antonio Damasio, for example, defines consciousness as "a state of mind in which there is knowledge of one's own existence and of the existence of surroundings." One needs a brain to be conscious, and science can study the brain. But since our consciousness seems different even from that of our closest cousins the chimps, it seems that we need to find out what is so different about our brains that produces a different, I hesitate to call “superior”, state of consciousness. In his book “Self Comes to Mind”, Damasio postulates that consciousness emerges only when the representational maps of sensory experience intersect with the encoded experiences of past that having a self provides, in other words, when self comes to mind. The autobiographical memory, the narrative of our lives, made possible by the evolution of language, is what constitutes the basis for consciousness, according to Damasio. Go to the discussion and link to a very interesting podcast featuring Dr Anil Seth, and Professor Chris Frith, two neuroscientists, and Professor Barry Smith, a philosopher.
How marijuana makes you forget. Marijuana smoking impairs short-term memory (working memory) in heavy users, or in people who use it frequently for medicinal purposes. How it did so was not known, up until now. A publication just came out in the prestigious journal Cell, describing that marijuana does not affect neurons, but rather astrocytes, which are non-firing brain cells who were believed to be simple protective cells. The scientists found a novel mechanism of communication (signaling) between neurons and astrocytes (in the photo, astrocytes are in red, neurons in blue), and it is especially exciting because it reveals a totally unexpected role of astrocytes in cognitive function. The scientists found that tetrahydrocannabinol (THC) , which is the active ingredient in weed, and the found the connection with the astrocytes by making genetically engineered mice lacking the CB1 receptor (the molecule that binds THC) in two different types of neurons. Since ablation of the receptor in the neurons did not prevent memory impairment, the researchers thought it had to be the astrocytes. They confirmed this by making another mouse model, lacking the CB1 receptor in the astrocytes. Marijuana no longer impaired memory in these mice. Sure, mice are not humans, but memory works pretty similarly in both species so it is reasonable to think that the same mechanism is responsible for memory impairment in humans smoking marijuana. Interestingly, a 2 year old study showed that people who smoke strains of marijuana containing high concentrations of cannabidiol (a non-psychoactive component) do not experience memory impairments; these strains can be used for medicinal purpose without unwanted side effects of short term memory loss. Now, where did I put my keys?
ZOOLOGY/CONSERVATION: Giant insect species thought extinct resurfaces after 80 years. This story has everything: mystery, adventure, an unreal rock formation, and a gigantic insect that came back from the dead. On Lord Howe island, in the South pacific off the coast of Australia, there lived a huge insect named Lord Howe stick insect (12 cm, or 4.8 inches long, the heaviest flightless insect in the world). As with many other creatures in the world, it disappeared from the face of the earth due to human action. In 1918, British ship was docked in that island for repair, stowaway rats colonized the island, and ate all the stick insects. Nobody has seen the six-legged giant, with the scientific name Dryococelus australis, for over 80 years, although rock climbers in the 1960s had seen fresh-looking stick insect carcasses 13 miles away from the island, on an impossible-looking volcanic rock formation, shooting up from the sea, called "Ball's pyramid." (in the photo). In 2001, two Australian scientists decided to investigate. They climbed the rock and found one single bush, called malaleuca, sitting on a crack in the rock. Below it, they found what looked like big insect feces. Since the Lord Howe Island stick insect was known to be nocturnal, they returned at night, risking their necks climbing the rock in the dark. Their efforts were rewarded by finding 24 live giant stick insects! All huddled together, under that one bush. They survived there for 80 years! How they got there is unknown, perhaps in a fisherman's boat, or floating on debris. Since these are the last of their species, the two scientists started a breeding program, with permission from the Australian government, with one male and one female. Check out the article for video of the first cute babies of these tenacious survivors. Life will find a way.
Science bits and news from other sites:
Female bonobos “advertise” their homosexual bonds. As you all know, bonobos (Pan paniscus) are famous for being very erotic and for using sex as a form of communication and bonding with members of the group, including both sexes, different age groups, etc. Bonobos live in matriarchal societies and bonding between females often involves face-to-face sexual contact (genital rubbing) with other females; this is possible because female bonobos have forward facing genitalia. Also, our cousins make a lot of noise during sex. But there is a pattern to the se vocalizations during sex. Vocalizations seem to be a way to advertise and boost their social status, because they occur mostly during encounters in which a lower-ranking female was “selected” by a higher-ranking female, and the intensity of the vocalization increases even further if the alpha female is within earshot.
Why don’t spiders stick to their own webs? I have often observed spiders running down their webs to catch a trapped fly. They can go very fast and they don’t seem to stick to their own webs. According to a recent article published in the journal Naturwissenschaften, this non-stickiness is a combination of fancy footwork and non-stick leg coating. Researchers at the Smithsonian Tropical Research Institute and University of Costa Rica have discovered that the spider’s legs covered by branching hairs and by a non-stick chemical coating. In addition, spiders’ leg motions minimize adhesive forces as they push against their sticky silk lines. The research was carried out on two web- tropical species, Nephila clavipes (in the photo) and Gasteracantha cancriformis, by recording the arachnids’ movements using a video camera with a powerful close-up lenses. A second camera was coupled to a low-power microscope to observe that individual droplets of sticky glue slide along the leg’s bristly hair, and to calculate the forces of adhesion to the web. The non-stick coating can be remove by washing the spiders’ legs with a mixture of hexane and water, and the researchers showed that after the washing, the spiders legs got stuck to the silky threads.
Jumping bacterial gene allows beetle to live off coffee beans. A rare example of beneficial gene transfer from bacteria to animal has just been published this week in Proceedings of the National Academy of Sciences. A bacterial gene was discovered in the genome of the coffee berry borer beetle (Hypothenemus hampei), a major coffee pest that originated in Africa but spread worldwide. The jumping bacterial gene allows the beetle to occupy a unique ecological niche by feeding on coffee beans. The bacterial gene allows the beetle to break down complex sugars in the coffee bean, and it is presumed to have come from bacteria in the beetle’s intestinal flora. The gene is called HhMAN1, and encodes a protein called mannanase, which breaks down the polysaccharide galactomannan. It is the first gene of this type to be discovered in an insect, and its sequence resembles closely resembles that of bacterial mannanase genes. The gene is located between two transposable elements, stretches of DNA that can jump from one location to another in a genome, that are the tell-tale sign of jumping genes, also called transposons. How the gene jumped from the bacteria to the beetle’s germline, is not known. Other cases of ecological significant horizontal gene transfer have been described, for example, carotenoid genes that determine aphid body color originated in fungi, and nematode worms have bacterial genes that allow the to digest plant cell walls.
Extreme lifespan in a clonal organism: millenary Mediterranean seag.... Last week we were discussing the oldest seed that was capable of germinating. Plants are a never ending source of surprises from a biological point of view, they are the longest living and also the biggest organisms in the world, including the gigantic parasitic fungus called Armillaria bulbosa that spans 635 m (0.39 miles), weighs around 21,000 pounds, and is over 1,500 years old. And now we have what botanists are calling “ MegaGrass.” The organism is Posidonia oceanica, a seagrass, which is actually a flowering plant with terrestrial ancestors, that lives in the Mediterranean Sea. To reproduce sexually, it makes floating fruits called “the olive of the sea” and washes up on shore as huge “hair balls”. The plant can also grow asexually, by propagating itself slowly but steadily by above or below ground stems called rhizomes. This sea grass is much bigger and older than anyone previously though, scientists have just published in PLoS ONE. Using DNA microsatellites as markers of genetic identity, the researchers sampled 40 locations in a region of 3500 km (~2200 miles) in the Mediterranean. They found very large clones in ~9% of samples, ranging from one to 15 kilometers (9.3 miles!) in size! Based on known growth rates for this seagrass, they estimate that these clones are tens of thousands years old, and in theory as old as 200,000 years old for the largest clones, meaning the parents of these clones were around in the Pleistocene! P. oceanica is among the slowest-growing and longest-lived plants on Earth and it dominates Mediterranean underwater meadows. It has no major predators. Unfortunately, due to human influence, these seagrass meadows are shrinking at a rate of about 5% per year, which several hundreds time faster than their growth rate.
New research shows childhood adversity causes changes in epigenetics. It is well known that stressful conditions during childhood (such as maltreatment, indifferent parents, or the loss of the parents) affect a person’s risk for psychiatric disorders such as anxiety and depression. But what is the biological mechanism for this increased risk? Recent research published in PLoS One suggests that childhood adversity can lead to epigenetic changes in the glucocorticoid receptor gene. Glucocorticoids are important components of the response to stress. Epigenetic changes are changes to the DNA that do not affect its sequence; epigenetic changes alter “marks” or “flags” in the DNA that then affect gene expression and ultimately, cell physiology. One of these marks is methylation of the DNA, which is known to regulate gene expression. There was previous data in mice that showed that the glucocorticoid receptor showed epigenetic changes in animals that experienced low levels of maternal care while they were pups. The researchers decided to investigate the glucocorticoid receptor of 99 healthy adult volunteers. Some of these study subjects had lost parents during childhood or had suffered abuse as children. The researchers found that people with a history of childhood stressors had more methylation of the glucocorticoid receptor (GR) gene, and that this epigenetic change caused a blunted cortisol response to a stress test. These results imply that the epigenetic changes in the glucocorticoid receptor gene lead to long-term changes in the ability of the body to respond to stress stimuli. Although much more research is needed, the data suggest a possible new strategy to help depressed or anxious patients who have suffered adversity as children, since there are certain drugs that are known to reverse the methylation pattern of DNA.