PHOTO OF THE WEEK: On the week of Earth Day, a fabulous photograph of the star that makes this all possible, the Sun. Here is an eruptive active region photographed using three color-coded wavelengths of extreme UV light. Go to the Solar Dynamic Observatory here for more stunning images of our star. Go to our Group The Daily Cosmos for great discussions and plenty of stellar eye candy.
VIDEO OF THE WEEK: Happy Earth Day: Our planet in high-resolution video. Make sure you watch it full screen and on a high-resolution screen if you can.
The sequence was created by James Drake, a student at the University of Victoria in Canada, using data from the Russian Federal Space Agency’s Elektro-L 1 satellite.
ASTROBIOLOGY/ZOOLOGY: Tardigrade eggs may survive interplanetary trip. The tardigrade Ramazzottius varieornatus, a microscopic aquatic animal also called "water bear," is one of the few known organisms that can survive the harsh conditions of a trip through space, such as intense radiation, extreme temperatures, and vacuum. Tardigrades are very peculiar little segmented animals, they are in their own Phylum (for comparison, we are in the Phylum Vertebrata). Tardigrades live in puddles, and when their habitat dries, they fall back into a dormant state called anhydrobiosis, and they can pop back to life when water is present again, even after a decade of being dried down! And to add to their extraordinary nature, an article just published in Astrobiology describes that their eggs would be capable of surviving a trip to another planet. A tea of NASA and Japanese astrobiologists in Japan devised extreme stress tests for the tardigrade's anhydrobiotic eggs. 70% percent of anhydrobiotic eggs survived temperatures as low as -320 degrees Fahrenheit and as high as 122 degrees Fahrenheit. Vacuum does not affect these eggs, and 50% of anhydrobiotic eggs endured 1,690 Grays of radiation (for comparison, we would day very quickly if subjected to <1% of that radiation amount!). Fully hydrated eggs did not survive any of the tests. It is not known how the eggs are capable to withstand such extreme conditions and still hatch after the ordeals. Who needs science fiction when right here on Earth, in a common puddle, we have such extraordinary creatures?
ZOOLOGY/ANATOMY: The curious case of the narwhal’s tusk. I watched the great BBC documentary "Frozen Planet" (I highly recommend it! David Attenborough is the best documentary narrator EVER); it has a great clip of narwhal pods swimming in narrow channels formed in the arctic ice by the arrival of the spring. Narwhals are fascinating because of their extraordinary asymmetrical canine tooth on the left side of their snout, protruding almost the length of the animal's body in the case of the males, from a weird opening in their upper "lip", not through their mouths. They are actually toothless except for that one long helical tusk that looks like a horn. In the documentary, two pods are swimming along the same narrow channel, one individual at a time, and when they meet, after communicating for a bit, both pods start swimming in the same direction, meaning one pod had to have decided to yield and go with the flow of the other pod. There was no fighting. I watched in amazement. And today I discovered a great blog post from Jerry Coyne, on a recent scientific article on the narwhals's tooth. It is full of amazing details, well worth the read. The tooth is a bit of a mystery from an evolutionary point of view: was it sexual selection? Was it an epigenetic by-product of selection? It apparently can detect water temperature and salinity, and the presence of fish. A truly extraordinary creature.
ANIMAL BEHAVIOR: Ravens remember relationships they had with others. Humans and other mammals have been shown to recognize the faces and voices of many individuals. And now. Markus Boeckle and Thomas Bugnyar from the Department of Cognitive Biology of the University of Vienna show that ravens differentiate individuals based on familiarity, and also classify their relationships as friends or foes, for at least three years. This is no surprise to me since ravens keep cropping up in the animal behavior literature as very intelligent birds. Ravens use separate calls for friends or enemies: if they hear a friendly individual they use a special friendly call, and when they respond to an enemy they use lower frequencies with rough auditory characteristics, a type of call already described in several animals as unfriendly, sort of like a dog growl. If ravens hear the calls of unknown individuals, they respond with increasingly lower and rougher calls, to increase the perceivable body size. We mammals do that all the time. Now we know some birds do this, too.
NEUROSCIENCE: Why can smells unlock forgotten memories?. We are such strongly visual animals that we rarely think about our sense of smell as being very important. Yet most of us have had this experience: smells can unlock memories, especially emotionally powerful memories, sometimes without us even realizing. Sometimes I catch a whiff of smell of the sea, on windy overcast days, when the sea gulls come a bit further inland, from the terrace of my apartment in Queens. And instantly I’m back to being a child in Montevideo: the same smell, the same weather; without even having to close my eyes, I’m in my childhood neighborhood, ready to go to school. Smell is evolutionarily the oldest sense; the chemicals in the air speak very directly to our brains. Even though our sense of smell pales in comparison to that of other animals, we have >1,000 different odorant receptors. We can discriminate between an incredible number of smells. Isn’t it fascinating that we do not have names for specific smells, like we have for colors? We simply say: “it smells like….” But why is smell so powerful in unlocking memories? One clue is that the hippocampus, the part of the brain involved in creating new memories, is located right next to the olfactory bulb. Another clue is that smells bypass the thalamic relay station that hearing or vision go through before being processed: smells travel directly to the olfactory bulb, they are “less processed” Is this why smells arise emotional memories, not easily put into words? Describing stuff or events in words can aid memory, but it also reduces the feelings associated with the memories.
ENVIRONMENTAL SCIENCES: Gulf aquatic wildlife deformities alarm scientists
Al Jazeera interviewed scientists studying the sea life in the Gulf region and report deformities in many sea creatures that have happened since the 2010 Deepwater Horizon BP oil pollution disaster. I guess the US media was too timid to do such a report. Dr. Jim Cowan from the Louisiana State University's Department of Oceanography and Coastal Sciences, reported fish lesions and sores; the fishermen themselves are astonished to see so many deformities. Local fishermen are finding mutated or deformed clawless crabs, eyeless shrimp, fish with tumors or sores, very frequently. Some fishermen reported that up to 50% of the shrimp they caught were missing not just their eyes, but also their eye sockets. The shrimp also seem to be immune-compromised and the size of the catch has dropped sometimes by 2/3. Part of the problem seems to be caused by the dispersants that BP used to dissolve the oil. The solvents in the dispersants are well known toxic and mutagenic compounds. They are also teratogenic, meaning that cause abnormal embryonic development. In addition, polycyclic aromatic hydrocarbons (PAHs) are being released from BP's submerged oil and these are likely to be responsible for the lesions and tumors in fish. Louisiana governor Bobby Jindal has released a statement that said the state continues to test its waters for oil and dispersants, as well as for PAHs, and that the Gulf seafood has consistently tested lower than the safety thresholds established by the FDA to pose a risk to human health. BP also released a statement: "Seafood from the Gulf of Mexico is among the most tested in the world, and, according to the FDA and NOAA, it is as safe now as it was before the accident." BP claims that fish lesions are common, were present prior to the disaster, and are caused by parasites and other agents. But crustacean biologist Darryl Felder (Department of Biology, University of Louisiana at Lafayette) who has been monitoring the area well both before and after the oil disaster began, said that after the disaster, they have found a much higher incidence of seafood with lesions, missing appendages, and other abnormalities. And even if they can be pinned down to microbes or parasites, in the end that does not mean that the chemicals are not responsible. The crustaceans appear to have eroded shells, increasing their vulnerability to parasites. Felder also found decreased diversity of crustaceans. Dr Andrew Whitehead, biologist at Louisiana State University, studied the genomic and physiological imprint of the spill on killifish, and showed a very clear signal of exposure to the toxic components of oil that coincided with the timing and the locations of the spill. Who are you going to believe, the fisherman and scientists, or BP?
BOMBSHELL OF THE WEEK: Priming for analytical thinking destroys belief in the supernatural. A very interesting experiment sheds light on why so many scientists are not religious or do not believe in the supernatural: it's not just the science knowledge in itself, but also the habit of thinking analytically. In this experiment carried out at the University of British Columbia in Vancouver, students were asked about their beliefs in god and other supernatural beings. Then several weeks later, a group of them were asked to perform tasks that supposedly primed analytical thinking, such as unscrambling sentences with the word "rational" in it, read text in hard-to-read-font, or even look at Rodin's statue The Thinker. The control group was asked to look at The Discus Thrower statue, read in easy fonts, or unscramble sentences with the word "shoe" or other such words in them. The group that was "primed" for analytical thinking reported less belief in God or angels, regardless of their initial belief.
Science bits and news from other sites:
Creepy people give us the chills (literally). As the social animals that we are, we are incredibly attuned to the signals other people send when communicating with us. And it’s already well known that emotions can literally be felt physically. For instance, people often feel physically cold when their social lives are unfulfilling or they are in a socially uncomfortable situation. And now, new research shows that creepy people literally give us goosebumps, we actually feel colder in the presence of weird people. But what is it about creepy people that we perceive as scary or eerie? In the iconic 1960 movie Psycho, Norman Bates gives us the willies because he is trying too hard to act normal, in other words to mimic other people’s speech pattern and body language. We normally display behavioral mimicry, as a way to build trust; for example, if we move to another country or area, we may pick up the mannerisms and accent of the locals. Friends tend to use common expressions or to use the same body language. This generally makes people feel good towards one another, but a recent experiment by social psychologist Pontus Leander, at the University of Groningen (Netherland), shows that if you overdo it, you will creep people out. In the experiment, a researcher separately interviewed 40 college undergraduates, subtly changing her behavior from person to person. In some cases she acted friendly and informal, dropping words like "awesome" into the conversation. In others, she was much more formal. At the same time, the researcher alternated between mimicking the students' body language and avoiding mimicking entirely. The students then filled out a survey that was designed to find out how cold or warm they physically felt. The students felt colder when the researcher’s social cues were contradictory, friendly but not mimicking body language, or too formal but mimicking body language, in other words, when her body language sent the opposite message. This is the awkward or creepy effect: you feel weirded out, even if it’s not possible to pinpoint exactly why. This is another demonstration of how important social clues are for us humans, even if we are not consciously aware of them.
Leeches are a bloody boon for conservation. Leeches may offer the best hope of finding the elusive endangered saola antelope (Pseudoryx nghetinhensis), one of the world’s rarest mammals, discovered in 1992, and in danger of extinction, with a population of a few hundred individuals. The animal has been found alive rarely, and the population is practically impossible to track. Thanks to a recent publication showing that the bloodsucking leeches can store DNA from their meals for several months, the saola conservation group I Vietnam is implementing an innovative way to measure biodiversity: to collect and sequence DNA left in the environment, from soil to leeches’ stomachs. A small reserve has been established in the saola’s only known habitat, the Annamite mountains at the border with Laos, where the last specimen was found alive in 2010, but died a few days after while in captivity. A more precise estimate of the antelope’s range would help to target conservation efforts, but camera traps failed to track the animals. Encouraged by the finding that goat DNA could be detected in leeches several months after feeding on goat blood in the lab, scientists send to the lab, tropical leeches (Haemadipsa spp.) collected from the Annamite range. Although no saola DNA was found in the leeches, DNA was found from other local animals such as the Truong Son muntjac deer (Muntiacus truongsonensis) and the Annamite striped rabbit (Nesolagus timinsi), which was discovered only a decade ago. New DNA sequencing techniques makes leech surveys relatively cheap, and DNA from hundreds of the animals could be combined and analyzed in a single experiment. Although this technique will not be useful in determining the number of animals, it will be useful for determining their range, since leeches preserve DNA from only their most recent blood meal. Collecting environmental DNA is becoming popular in recent years: the diet of leopards was studied by sequencing the DNA in its feces, and ancient Siberian habitats were reconstructed from DNA preserved in permafrost. Recently, Australian scientists have found DNA from critically endangered species and potentially toxic plants in traditional Chinese medicines. Environmental DNA studies are termed “meta-bar-coding”, because they rely on DNA bar codes, i.e. short DNA sequences that uniquely identify a species.
Male bowerbirds attract more mates by being gardeners. Here is another fascinating blog post by the great science writer, Ed Yong. Apparently male spotter bowerbirds intentionally, or inadvertently, cultivate a shrub called “bush tomato”, and do not eat its green fruit or purple flowers, but rather use it to make his nest more attractive to females. The spotted bowerbird is so far the only animal, other than humans, that grows a plant for purposes other than food. Bowerbirds are known for building very elaborate structures, called bowers, that are used in courtship displays; they decorate them with any sort of found objects, such as seashells, etc. Each species of bowerbirds has a predilection for certain colors of shapes for their decorations. But the spotted bowerbird is the only one to cultivate its own decorations. Although the birds do not tend to the soil, or plant the shrubs, they are doing something to keep the plants happy, because bush tomato plants become more abundant after the male bowerbird move into the territory, and not the other way around. They could simply be plucking away shriveling fruits or leaves, and thus leaving only the healthiest fruits around from which new plants will germinate. The bird is very fastidious and clears leaf litter and other foliage from their territory, leaving plenty of bare ground that is the ideal habitat for bush tomato seeds to germinate. It is clearly a symbiotic relationship. The shrub must be very appealing to females, because the more bush tomatoes he has, the more mates he gets. A male bird will stay in the same bower for up to 10 years, so it is really important that he keeps his bower very fruity and very bushy if he is to leave a lot of progeny. From an evolutionary point of view, the relationship of plant and bird is fascinating: bush tomatoes from plants near bowers have a slightly greener hue, and are more lightly colored, exactly the type of looks that the birds find most attractive. The bird and the plant are evolving together. In a way, this is similar to our relationship with domesticated plant species that we eat. The original article can be found here.
Great tits join mobs with neighbors they know. Let’s get this off our chests (no pun intended): this is NOT about a pair of extraordinary mammary glands; it’s about little colorful songbirds (Parus major). These little birds are very protective parents, swooping down to attack any size intruder or predator that approaches their nest. They form what is called “joint mobbing,” with many birds joining forces to attack the predators. This is rather common, but mostly in birds such as sterns or gulls that nest in very big colonies. But what is peculiar about the great tits’ mobbing, is that they will join in the attack only if they hear alarm calls from birds they know, from the next-door neighbors. The study was carried out by University of Oxford scientist Ada Grabowska-Zhang and her team. To determine if the birds reacted to the alarm calls of a familiar neighbor, the team studied birds in a nestbox population that they had monitored for their research over several years. She verified which birds were which by placing paint at the entrance of the nests so the birds would get a spot of color on their bellies when they swooped out of their nest. Then they provoked attacks by approaching their nest and making some noise. Grabowska-Zhang could then verify that when the parents in the threatened nest started making alarm calls, it was their familiar neighbors, those that had lived next door for at least one previous breeding season that responded to the calls and joined the attack. Grabowska-Zhang explained that this behavior helps these neighborhood groups collectively raise more chicks and defend against predators. She must have waited her whole life to say the sentence: “It's sort of great tit tit-for-tat."
“Brain freeze” finally explained. Most people have experienced “brain freeze’, also known as “ice cream headache” at least once in their lives. Some of us get it very often. I get it all the time. Incredibly, the exact cause of this phenomenon was not quite understood until now. Based on the fact that migraine sufferers get brain freeze more often than other people, researchers thought there might be a common cause behind these two types of headache. Since many headaches occur because of local changes in blood flow, a team at the Department of Veterans Affairs New Jersey Health Care System, induced brain freeze in 13 healthy volunteers and studied blood flow in their brains. Brain freeze is an ideal system to study headaches in the lab because it is easy to induce and easy to resolve without the use of drugs. In this study, the blood flow in several brain arteries was measured using transcranial Doppler while the volunteers either sipped iced water or room temperature water with the straw against the upper palate first sipped ice water with the straw pressed against their upper palate. The volunteers indicated the onset of brain freeze by raising their hands, and also to indicate when it was over. The data showed that one particular artery, the anterior cerebral artery, dilated rapidly and flooded the brain with blood in conjunction to when the volunteers felt pain and constricted as the volunteers’ pain disappeared. Since the skull is a closed structure, the sudden influx of blood causes painful pressure and induces pain. The ensuing vasoconstriction is likely a way to rapidly decrease the pressure before it becomes dangerous. These findings could eventually lead to new treatments for different kinds of headache, if similar mechanisms are seen with other types of headache.
The genetic composition of the Scots: they’re just like the English! As the discussion “What is Human Nature” hints at, one of the things that makes us humans is how we all like to gossip. Here is my gossip post for the day: The scots are not pure descendants of Celts and glorious Vikings, but they mostly are just like the English, if you look at their DNA. Bonnie Prince Charlie himself had English ancestors. Around 1,000 Scots have been tested recently as part of the Scottish DNA project, started by Dr. Jim Wilson, a geneticist at Edinburgh University, and Alistair Moffat, a journalist and current rector of St Andrews University. The preliminary results revealed some pretty interesting facts. Around 1% of Scotsmen (~26,000 individuals) are descended from the Berber and Tuareg tribesmen of the Sahara, going back 5,600 years. Roughly 100 different groups of male ancestry (Y chromosome) have been found so far, from all over Europe, and further, and 157 types of mitochondrial DNA from Europe, Asia and Africa. Among the gossip part, it was revealed that the actor Tom Conti is related to Napoleon Bonaparte, and that the Scottish comedian Fred Macaulay had Irish ancestors who were probably slaves in the 9th century. This suggests that a slave at some point had sex with his owner’s wife, and that’s how his DNA entered the Macaulay line. The Royal Stewart DNA is found in ~ 15% of men with that last name, which means there are thousands of Scots with some royal blood walking around. Mr Moffat thinks that Scotland was populated after the last ice age, and has been the final destination for many journeys over 11,000 years, because it was hard or impossible to go further north. The basic lineage is the same for Scotland and England, since almost everybody came from the south. The Scots have a bit more Vikings and more early Irish, but the basic composition seems to be the same as the English. Not sure why anyone is very surprised.