Apr 4, 2015
Scientists studied proteins found in cells, known as histones, which are not part of the genetic code, but act as spools around which DNA is wound. Histones are known to control whether or not genes are switched on.
Researchers found that naturally occurring changes to these proteins, which affect how they control genes, can be sustained from one generation to the next and so influence which traits are passed on.
The finding demonstrates for the first time that DNA is not solely responsible for how characteristics are inherited. It paves the way for research into how and when this method of inheritance occurs in nature, and if it is linked to particular traits or health conditions.
It may also inform research into whether changes to the histone proteins that are caused by environmental conditions -- such as stress or diet -- can influence the function of genes passed on to offspring.
The research confirms a long-held expectation among scientists that genes could be controlled across generations by such changes. However, it remains to be seen how common the process is, researchers say.
Scientists tested the theory by carrying out experiments in a yeast with similar gene control mechanisms to human cells. They introduced changes to a histone protein, mimicking those that occur naturally, causing it to switch off nearby genes. The effect was inherited by subsequent generations of yeast cells.
The study, published in Science, was supported by the Wellcome Trust and the EC EpiGeneSys Network.
Read more at Science Daily
So now that we’ve gotten that out of the way, here’s another burning question: Where does lightning strike most frequently on the planet? As it turns out, those brainy folks at NASA have the answer.
Between 1998 and 2013, NASA’s Tropical Rainfall Measuring Mission and OrbView-1/Microlab satellites gathered data on the number and location of lightning flashes worldwide, and what they found is shown on the map above. As it turns out, lightning tends to happen most often in areas closest to the equator, and more often over land than over the oceans.
That makes sense, because as NASA’s Earth Observatory website explains,solid earth absorbs sunlight and heats up faster than water. That results in stronger convection and greater atmospheric instability, which leads to the production of the sort of storms that produce lightning.
The spots on the planet with the highest amount of lightning turn out to be Lake Maracaibo in northwestern Venezuela, where the combination of heat, humidity and wind from the surrounding Andes mountain range causes spectacular storms, and the far eastern part of the Democratic Republic of Congo.
According to Reuters, the Lake Maraciabo area has lightning storms 300 nights each year, and each kilometer of the area is hit by 250 lightning strikes annually.
NASA scientist Daniel Cecil noted on the Earth Observatory website that the new map is far more detailed than previous efforts to chart global lightning. “The longer record allows us to more confidently identify some of these finer details,” he said. “We can examine seasonality, and variability through the day and year-to-year.”
From Discovery News
Apr 3, 2015
The finding not only throws off some common perceptions of what paleo men actually ate, but also adds some mystery to the fully intact skeleton found in 1996 in Kennewick, Washington.
The ancient human, who stood at 5 feet 7 inches, was found in a region where four-footed game were aplenty. So why wasn't he hunting them?
"The only theory I can suppose for why he chose not to eat local game (which was abundantly available) is that he had some deeply-held belief system that caused him to reject terrestrial meat from his diet," Henry Schwarcz, professor emeritus in the School of Geography and Earth Sciences at McMaster University, said in an email to Discovery News.
"It is hard to imagine how a people could persist in such a belief system as long as these data suggest."
Schwarcz added that his research doesn't exclude the possibility that Kennewick Man also ate plant-based foods like nuts and berries (which happen to also be on the Paleo diet menu).
Another possibility is that the ancient man may have been killed far from his main home. His remains were found some 370 miles inland -- but perhaps his home was closer to the Pacific Ocean.
"Certainly his diet is matched more closely by consumption of marine mammals that live mainly on the coast," Schwarcz said.
Schwarcz, renowned for his research in isotopic analysis of ancient bones, based his findings on his analysis of collagen in a small bone fragment from the famous and controversial skeleton. He presented his work at the recent annual meeting of the American Association of Physical Anthropologists in St. Louis.
Previous research has shown that the man died at about age 40. He had lived with an arrowhead stuck in his hip and also suffered from five broken ribs, two dents in his skull and a bum shoulder (probably from throwing so many spears).
"He was a strong, robust man (based on the appearance of his skeleton) who had managed to survive at least one attack by another human," said Schwarcz. "He should have been an able fisherman/hunter."
Kennewick man is one of the oldest and most complete skeletons found in North America. Recent estimates date the remains to between 8,400-8,690 years old. The skeleton became the subject of an eight-year-long lawsuit between scientists who sued the federal government (along with several Native American tribes) to prevent the bones from being turned over to regional tribes for reburial.
In 2004 the Ninth Circuit upheld a ruling that Kennewick Man is not related to any of the present-day tribes and therefore can remain at its current location at the Burke Museum of Natural History and Culture in Seattle. The debate over his ethnicity and origins -- and what should happen to him -- continue today.
Read more at Discovery News
The animal would have been somewhat of an "alien" along the Danube River in Tulln, Austria, the researchers said, calling it a "sunken ship in the desert."
"Camels are alien species in Europe and Austria, the town of Tulln is closely situated to the large river/stream of the Danube," said Alfred Galik, a researcher at the University of Veterinary Medicine Vienna and one of the scientists who worked on the study detailing the discovery. The "sunken ship" phrase "should bring together this buried/sunken ship of the desert — with Tulln and the Danube a place where no camels naturally appear," Galik told Live Science in an email.
And rather than a beast of burden, this camel was likely a valuable riding animal, as the researchers found no clear signs of arthritis on the camel's bones. Rather, symmetrical marks on the shoulder blades and parts of the humerus bones likely resulted from the stress of a rider getting on and off of the camel.
The camel also had unusual parents: It was born to a Bactrian camel (two-hump) dad and a dromedary (one-hump) mom, the researchers found after looking at the bones and analyzing the camel's DNA. The cross between the one-hump dromedary and the two-hump Bactrian resulted in a camel with one large hump, Galik said.
"Such crossbreeding was not unusual at the time," Galik said in a statement. "Hybrids were easier to handle, more enduring and larger than their parents. These animals were especially suited for military use."
As for how the camel got to Tulln, the researchers speculated that perhaps it came from the Ottoman army when Tulln was being attacked, Galik said.
"That means the cadaver was not butchered, and the flesh was not used — what remains as an untypical behavior, especially in times of war," Galik said. The Tulln inhabitants may not have wanted to eat the flesh of the camel because it was such an "alien animal," he added.
Read more at Discovery News
That's according to new research out of Duke University that documented male mice changing their tunes, literally, as social contexts changed. And the kicker? The fancy tunes were, perhaps no surprise, a hit with the ladies (and, hey, they could always blame the drummer if things did not go well).
The news isn't just of interest to fans of singing mice. The findings, and further study on what mice can or can't do vocally, may have implications for autism spectrum disorders in humans, say the researchers.
Mice "sing" using what are called "ultrasonic vocalizations" -- high-pitched sounds that escape the human ear. To listen in on them, the researchers used special microphones to record male mice singing in two social contexts: smelling, but not seeing, a female; and interacting with her in person (as it were).
In the first case, the male was presented with female urine to sniff, but there was no lady in sight for him to woo. So what's a mouse in the mood to do? Sight unseen, the male sang to his intended a loud, complex song (defined by the scientists as a series of utterances or syllables, sometimes with a tempo).
In the second case, the female was placed in the same container with the male. Finally whisker-to-whisker with the object of his desire, the romeo mouse sang longer, simpler, quieter songs. (The video below offers a chance to compare the male's vocal chops in both cases.)
Read more at Discovery News
|The elephant fish chimaera and its characteristic snout. No, that's not what I'm talking about with the penis stuff. That's another structure entirely. I mean, that there would be a weird-looking penis.|
Well, it turns out there are real-life chimeras—at least in name anyway—that may be even stranger, on account of actually being real. Only these are called chimaeras, and they don’t breathe fire, largely due to the fact that they live in water. And while superficially chimaeras resemble sharks, they’re only a distantly related, ancient species, having appeared some 400 million years ago. These are truly some of the most enigmatic and unique fishes of the deep sea. Oh, also, they don’t have penises on their heads, contrary to what you may have heard.
One of the few people who knows a damn thing about the mysterious chimaeras is evolutionary biologist Douglas Long of St. Mary’s College in Moraga, California. The problem, he says, is that these things usually live too deep to get caught in fishing nets (well, I guess that’s actually a good thing), and it’s not like humans are spending a tremendous amount of time sending submersibles down there. But we can make our best conjectures, and we’ll start with the remarkable snouts of the so-called rhinochimaeras.
Like sharks, chimaeras probably hunt down their food by following the trail of electricity emitted when creatures move their muscles. “As they’re swimming above the substrate, it’s believed that they can somehow detect buried invertebrates that are under the sediment, or sticking out of the sediment,” says Long. “Then they sort of dive in and take them out.” Nobody’s actually seen this happen, he notes, but the chimaera’s snout is packed with nerves and structures for electrosensory perception. And while it’s likely that all chimaeras have this ability, the rhinochimaeras—one of which you can see meandering below—could have adapted to supercharge this power with their formidable schnozzes, utilizing more surface area to pack in more sensors.
|An incredible rhinochimaera looks a bit like Dumbo. Only those are fins, not ears. And that isn’t technically a nose. But whatever.|
Chimaeras of course have their own predators. For those, they come prepared with a defensive spine at the base of their dorsal fin—one that, in at least some species, can deliver toxins. Exactly how that toxin is delivered isn’t quite clear yet, according to Long. The chimaera known as the Pacific ratfish, for instance, doesn’t seem to have an obvious venom gland. That means it may not deliver venom like a rattlesnake, with its needle-like fangs. Instead, it might be more of a toxic slime that coats the chimaera’s spine, like stingrays do it (also, FYI, one of the largest freshwater fishes in the world, the 16-foot giant stingray, sports a stinger that’s 15 inches long). In the rhinochimaeras, it may be that the spine isn’t toxic at all, and is just meant to inflict good old trauma.
For the Last Time, Chimaeras Do Not Have Penises on Their Heads
The vast majority of fish have this funny habit: When a girl fish and a boy fish love each other very much, they just dump their gametes into the ocean. With any luck, the two will mix and make babies. But not sharks and chimaeras—they’re internal fertilizers. And internal fertilization can be a bit difficult if you don’t have limbs to help you grasp your partner.
Male sharks have highly modified fins known as claspers (those two dangling bits you see on great whites, for instance), which they insert into females to deliver sperm. “One of the issues is that you need to get some leverage to be able to insert this into the female,” says Long. “And so with sharks and rays the males will frequently bite onto the females, bite onto the fin or even bite onto the body so they can get leverage and slip that clasper in.”
Male chimaeras have these claspers as well, but they’re also equipped with a specialized club-like structure on their heads. This is covered in small hooks, and is thought to help the male hold onto the female, though no one has ever seen this in action to confirm it. “And the problem that I’ve had with people is that they’ve said, ‘Oh, it’s the shark that has a sex organ on the head,’” says Long. “And somebody will write another article saying ‘the shark with the penis on the head.’” Well, sir, that stops right here.
First of all, it’s not a shark. And second, while the structure is probably helping the chimaera fertilize the female, it’s definitely not a penis. Sharks and chimaeras don’t even technically have penises in the first place. “But it is involved in copulation, the same way that your arms are when you’re with your significant whoever, holding them close and hopefully being a little more successful by using your arms rather than not using your arms.” (While I declared a few weeks ago that science’s greatest analogy ever was a researcher telling me that a female octopus wringing out a male’s disembodied, sperm-packed arm onto her eggs was like squirting soy sauce onto rice, Long’s analogy here is a close second.)
Now, while some mother sharks lay eggs, others will allow the young to develop inside themselves and emerge relatively developed. Chimaeras, though, have a rather more peculiar way of going about things: Females drag a pair of eggs along with them by a tendril. “She’ll lay the eggs, but that little tendril will still be in her cloaca,” says Long. “She’ll be swimming around dragging the two eggs behind her, and some people think that might actually be a form of what’s called egg guarding.” Instead of dropping her eggs on the seafloor and leaving them to the mercy of predation, she just totes them along. Then again, Long cautions that it may be that she just takes her sweet time laying them, and that they eventually do drop and settle on the seafloor.
Read more at Wired Science
Apr 2, 2015
Spiders have developed a unique way to move around: Rather than relying mainly on muscles to move, they use a fluid called hemolymph, which is their blood. When hemolymph flows into their tubelike legs, the limbs extend and their flexor muscles bend the legs at the joint, causing that fluid to flow back out.
Temperature can change the thickness, or viscosity, of hemolymph, said the study's senior author, Anna Ahn, an associate professor of biology at Harvey Mudd College in California.
"I always tell people, 'I can convince you that spiders are cool,'" Ahn said.
The researchers studied eight adult Texas brown tarantulas (Aphonopelma hentzi). They tested the spiders' speed and agility at four different temperatures: 59, 75, 88 and 104 degrees Fahrenheit (15, 24, 31 and 40 degrees Celsius). When the spiders were placed in temperatures that were higher or lower than that range, they tended to turn around and get into an attack stance, Ahn said.
Spiders have two joints along each leg, and the one closest to the body typically extends first when they're walking or running. To calculate each spider's coordination, the team painted a white dot on each of the joints on a foreleg and hind leg, and compared the angle of the two joints on each leg. Then they filmed the spiders scuttling down a runway.
"They're actually a little skittish and shy," she said. "All you had to do was blow a puff of air on them and they would run away from you."
At lower temperatures, the spiders moved more slowly, likely because the hemolymph was more viscous than at higher temperatures, Ahn said. Still, lower temperatures had a perk: The tarantulas had more coordination when the thermometer read 59 or 75 F.
"But at the higher temperatures, and the faster running speed, the two joints were less coupled," or less coordinated, Ahn said. "The two joints on each leg were a lot less well controlled at the higher temperatures."
To give an idea of the spiders' speed, imagine a 2.1-inch (5.5 centimeters) tarantula. On average, the spiders moved about four body lengths a second at 62 F (17 C), and about 10 body lengths a second at 100 F (38 C), a 2.5-fold increase.
But it would be difficult to catch the tarantula's unsteadiness with the naked eye. They move fast, and the researchers had to slow down the video in order to calculate the angle of each leg. Regardless, the spiders' instability at high temperatures may explain why some tarantulas emerge at dusk, when the weather is cooler, Ahn said.
Read more at Discovery News
The food wasn't eaten during a formal seated gathering at a rectangular table, as shown in many religious art paintings, but with Jesus and his apostles reclining on floor cushions, as the Romans did at that time.
The study by two Italian archaeologists relied on Bible verses, Jewish writings, ancient Roman works and archaeological data to investigate the eating habits in Jerusalem at the beginning of the 1st century A.D.
"The Bible discusses what happened during that dinner, but it doesn't detail what Jesus and his 12 dining companions ate," Generoso Urciuoli, archaeologist at Italy's Petrie center and author of the Archeoricette blog on ancient food, told Discovery News.
Urciuoli, who specializes on the history of early Christianity, and co-author Marta Berogno, archaeologist and Egyptologist at Turin Egypt's museum, will publish their findings next month in the book "Gerusalemme: l'Ultima Cena" (Jerusalem: the Last Supper).
"The starting point is the assumption that Jesus was a Jew. He and his disciples observed the traditions transmitted by the Torah and its food related bans," Urciuoli said.
Commemorated today by Christians, the Last Supper is the final meal that, according to the Gospel, Jesus shared with his closest disciples in Jerusalem hours before he was turned over by Judas to Roman soldiers and crucified.
The scene was immortalized by Leonardo Da Vinci, but the masterpiece, one of the world's most famous and powerful paintings, isn't historically accurate, according to Urciuoli.
"Leonardo's mural derives from centuries of iconographic codes. Embodying the sacrament of the eucharist, the Last Supper has a very strong symbolic meaning and this does not help the historical reconstruction," Urciuoli said.
Putting together historical data and clues from artworks such as third century A.D. catacombs paintings, the researchers were able to reconstruct food and eating habits in Palestine 2,000 years ago.
The picture that emerges is completely different from traditional renderings of the Last Supper. The dinner, which happened on the upper room of a house in Jerusalem, wasn't a seated gathering at a rectangular table.
"At that time in Palestine, food was placed on low tables and guests ate in reclining position on floor cushions and carpets," Urciuoli said.
Plates, bowls and jars were likely made of stone. Evidence for 1st century A.D. stone vessels has been found at numerous sites near Jerusalem and Galilee.
"Jews that observed the rules of purity used stone vessels because they were not susceptible to transmitting impurity," Urciuoli said.
"Another possibility is the use of fine red terra sigillata pottery, an international trend at that time," he added.
The position of the guests around the table followed a precise rule, and the the most important were those at the right and left of the main guest.
"Verses from the gospels of John indicate Judas was very close to Jesus, probably to his immediate left. Indeed, we are told that Judas dipped bread into Jesus's dish, following the practice of sharing food from a common bowl," Urciuoli said.
Urciuoli and Berogno narrowed the search for the food present at the Last Supper by reconstructing two other important meals mentioned in the New Testament, the wedding at Cana, which records the water to wine miracle, and Herod’s banquet, famous for the beheading of John the Baptist.
"The wedding at Cana allowed us to understand the Jewish religious dietary laws, known as kashrut, which established what foods can and cannot be eaten and how they must be prepared. On the other side, Herod's Banquet allowed us to analyze Roman culinary influences in Jerusalem," Urciuoli said.
Apart from wine and bread, tzir, a variant of the Roman fish sauce garum, was likely present both at the wedding of Cana and Herod’s banquet, as well as at the Last Supper, the authors said.
Detailing their research in the book, Urciuoli and Berogno also hypothesize the Last Supper might have occurred during the Feast of Booths or Tabernacles, an autumn feast commemorating the years the Israelites spent in the desert in fragile dwellings after the exodus.
But according to the Gospel of Mark, Jesus prepared for the Last Supper on the "first day of Unleavened Bread, when they sacrificed the Passover lamb."
Read more at Discovery News
Currently studying the “Pahrump Hills” region at the base of Mount Sharp in the center of Gale Crater, this new view snapped by Curiosity on March 18 shows a work site Curiosity’s mission scientists call “Garden City.” This area is interesting as it shows two-tone mineral veins protruding from the surrounding rock.
The tough mineral veins were formed in Mars’ ancient wet past and they are sticking out of the rock up to 6 centimeters (2.5 inches) high. This means that the veins formed within the rock and the softer surrounding bedrock has since eroded away.
When comparing the geology of this particular area with the rocks that Curiosity has analysed in lower sections of Mount Sharp, a story emerges Mars’ ancient geological history.
“Some of (the mineral veins) look like ice-cream sandwiches: dark on both edges and white in the middle,” said Linda Kah, Curiosity science-team member at the University of Tennessee, Knoxville, in a NASA Jet Propulsion Laboratory news release. “These materials tell us about secondary fluids that were transported through the region after the host rock formed.”
Like previous rocks studied by Curiosity, the prominent veins at Garden City were formed when water flowed through cracks in bedrock, depositing minerals inside these fractures. The chemistry of the rock neighboring the fractures became altered and these tough veins formed. Previously, the robotic geologist has found other bright veins rich in calcium sulfate.
However, Garden City appears to be different from previous samples — the darker material in the veins suggest an early episode of water on Mars, whereas the brighter mineral deposits shows a later episode of water flow.
“At least two secondary fluids have left evidence here,” added Kah. “We want to understand the chemistry of the different fluids that were here and the sequence of events. How have later fluids affected the host rock?”
Curiosity has been studying rocky configurations since landing on the Martian surface in 2012.
Over the past 6 months, the rover has been focused on Pahrump Hills, studying the layers of rock spanning an elevation of only 10 meters. Garden City is the highest point (so far) of this survey and there are very obvious changes in the mineral history over this small cross section.
“We investigated Pahrump Hills the way a field geologist would, looking over the whole outcrop first to choose the best samples to collect, and it paid off,” said David Blake of NASA’s Ames Research Center, Moffett Field, Calif., and principal investigator for Curiosity’s Chemistry and Mineralogy (CheMin) instrument.
Read more at Discovery News
Data from NASA's Gravity Recovery And Interior Laboratory (GRAIL) mission suggests that lava tubes on the moon could have diameters in excess of more than half a mile (1 kilometer). These features could support future long-term human exploration on the moon, offering shelter from cosmic radiation, meteorite impacts and the wild temperature swings of lunar day and night, according to scientists with Purdue University who performed the study.
Purdue University researchers presented their research during the Lunar and Planetary Science Conference held here March 16-20.
Beneath the Moon
According to Jay Melosh, a Purdue University distinguished professor of Earth, atmospheric and planetary sciences, the edges of the lava cool as it flows to form a pipe-like crust around the flowing river of lava. When the eruption ends and the lava flow stops, the pipe drains leave behind a hollow tunnel.
"There has been some discussion of whether lava tubes might exist on the moon," Melosh said in a Purdue press statement. "Some evidence, like the sinuous rilles observed on the surface, suggest that if lunar lava tubes exist they might be really big."
The presence of sublunarean voids has recently been confirmed via the observation of "skylights" in several lunar maria.
David Blair, a graduate student in Purdue's Department of Earth, Atmospheric and Planetary Sciences, led the study that examined whether empty lava tubes more than 1 kilometer wide could remain structurally stable on the moon.
The Purdue team found that if lunar lava tubes existed with a strong arched shape like those on Earth, they would be stable at sizes up to 5,000 meters, or several miles wide, on the moon.
"This wouldn't be possible on Earth, but gravity is much lower on the moon and lunar rock doesn't have to withstand the same weathering and erosion," Blair reported. "In theory, huge lava tubes -- big enough to easily house a city -- could be structurally sound on the moon."
Blair and his team found that a lava tube's stability depended on the width, roof thickness and the stress state of the cooled lava. They modeled a range of these variables.
The researchers also modeled lava tubes with walls created by lava placed in one thick layer and with lava placed in many thin layers.
Read more at Discovery News
Apr 1, 2015
The dino couple, named Romeo and Juliet since they are reminiscent of Shakespeare's famous doomed lovers, were entombed together for over 75 million years, according to a new study in the journal Scientific Reports.
Key to the research was figuring out the sex of the dinosaurs.
"Determining a dinosaur's gender is really hard," lead author Scott Persons said in a press release. "Because soft anatomy seldom fossilizes, a dinosaur fossil usually provides no direct evidence of whether it was a male or a female."
Persons, a paleontologist at the University of Alberta, and his team compared the remains of the bird-like dinosaurs, which were oviraptors (avian-resembling two-legged predators), with the anatomy of modern birds.
The researchers found evidence that the dinosaurs sported long feathers on the ends of their tails. The feathers were not suitable for flight, so they must have served some other purpose.
"Our theory," explained Persons, "was that these large feather-fans were used for the same purpose as the feather fans of many modern ground birds, like turkeys, peacocks, and prairie chickens: they were used to enhance courtship displays. My analysis of the tail skeletons supported this theory, because the skeletons showed adaptations for both high tail flexibility and enlarged tail musculature — both traits that would have helped an oviraptor to flaunt its tail fan in a mating dance."
Taking their analysis a step further, the research team discovered that one of the two dinosaurs had larger, specially shaped tailbones. The differences were expected, and match that of some male versus female birds today. They provide strong evidence for sexual dimorphism, meaning distinct differences in the size or appearance between the sexes of an animal.
Read more at Discovery News
Containing more than 1,000 people, the large graveyard was discovered three years ago beneath the Old Divinity School at St John’s College during refurbishment of the Victorian building. Details of the finding have only now been made public.
A report published in the current issue of the Archaeological Journal reveals that 400 perfectly preserved human skeletons were uncovered, along with the disarticulated and fragmentary remains of up to 1,000 more individuals.
“It’s one of the largest medieval hospital osteoarcheological assemblages from the British Isles,” dig director Craig Cessford, from the university’s department of archaeology and anthropology, said.
Mostly dating from the 13th to 15th centuries, the remains lay in burials belonging to the Hospital of St John the Evangelist. The building, from which St John’s College takes its name, stood opposite the graveyard until 1511 and was established to care for “poor scholars and other wretched persons.”
“Pregnant women, lepers, the wounded, cripples and the insane were all specifically excludedfrom its care,” Cessford wrote.
People were laid to rest without coffins, and even without shrouds, confirming the cemetery was mainly for the poor. Jewellery and personal items, including a crucifix, were only present in a handful of burials.
“Items were found in graves that might represent grave-goods, but their positions were ambiguous and it is equally possible that they represent residual material from earlier activity at the site,” Cessford said.
Anthropological examinations of the remains revealed there was a roughly equal gender balance, with the majority of individuals having died between around 25 and 45 years old.
The archaeologists also noted the complete absence of infants, normally expected in a medieval hospital, and a relative lack of remains of young women, which can be explained by the Hospital’s Augustinian ordinance from 1250 to exclude pregnant women from its care.
Some of the skeletons also did not fit their graves.
“This suggests that some, but not all of the graves may have been dug in advance of being needed,” Cessford wrote in the Archaeological Journal.
Read more at Discovery News
This finding comes from evidence suggesting the mysterious human relative was buried some 3.7 billion years ago, more recently than thought. This new date may one day help shed light on which region and which species gave rise to humanity, scientists added.
Among the earliest known relatives of the human lineage definitely known to walk upright was Australopithecus afarensis, the species that included the famed 3.2-million-year-old Lucy. Australopithecines are the leading candidates for direct ancestors of humans, living about 2.9 million to 4.1 million years ago. (The human lineage, Homo, is thought to have originated about 2 million years ago.)
While Australopithecus afarensis dwelled in eastern Africa, another australopithecine nicknamed Little Foot, due to the diminutive nature of the bones, lived in southern Africa. Discovered about 20 years ago by paleoanthropologist Ronald Clarke from the University of the Witwatersrand in South Africa, Little Foot apparently fell down a narrow shaft in the Sterkfontein Caves. This left behind a nearly complete skeleton that could yield key insights on human evolution.
It remains debated what kind of australopithecine Little Foot was. Many scientists think Little Foot was a member of Australopithecus africanus, which had a rounder skull housing a larger brain and smaller teeth than did Lucy and the rest of Australopithecus afarensis. However, Clarke and others suggest Little Foot belonged to another australopithecine known as Australopithecus prometheus, which had a longer, flatter face and larger cheek teeth than Australopithecus africanus.
It was impossible to fit Little Foot into the human family tree with any certainty because "ever since its discovery, the age of Little Foot has been debated," said lead study author Darryl Granger, a geochronologist at Purdue University in West Lafayette, Indiana. If researchers can figure out when Little Foot arose, they might be able to better pinpoint which Australopithecus species and which part of Africa ultimately gave rise to Homo.
Now, Granger and his colleagues have found evidence that Little Foot lived at about the same time as Lucy. Even so, the fossil doesn't give a definitive answer on Little Foot's species.
"The most important implication from dating Little Foot is that we now know that australopithecines were in South Africa early in their evolution," Granger told Live Science. "This implies an evolutionary connection between South Africa and East Africa prior to the age of Little Foot, and with enough time for the australopithecine species to diverge."
This in turn suggests that other australopithecines — and, later, humans — "did not all have to have derived from Australopithecus afarensis," Clarke told Live Science. "There could well have been many species of Australopithecus extending over a much wider area of Africa."
Dating Little Foot
The researchers first tried dating the age of Little Foot more than a decade ago "and got an age of around 4 million years, which would place Little Foot among the oldest of the australopithecines," Granger said.
However, dating the age of fossils in caves is extraordinarily complicated because material can wash into a cave from the outside and easily confound analysis. When others dated the age of minerals known as flowstones near Little Foot, they found those cave formations originated about 2.2 million years ago. "I was disappointed, but I could see nothing wrong with their ages," Granger said.
But a recent study found these nearby flowstones did not reflect Little Foot's age because they were not part of the same layer of rock that held the fossils and therefore did not form at the same time. In the new analysis, Granger and his colleagues pinpointed the fossil's age by measuring levels of aluminum and beryllium isotopes in quartz in the same rock layer as the skeleton.
The researchers also found that the earliest stone tools in the same cave date back to about 2.2 million years ago. This is a similar age to early stone tools found elsewhere in eastern and southern Africa. "This implies a connection between South African and East African hominids that occurred soon after the appearance of stone tools," Granger said.
Read more at Discovery News
The conundrum centered on how the cores of planets as far away from the sun as Jupiter and Saturn had time to wrap themselves in giant blankets of gas, rather than migrate inward at an early stage, stifling their growth.
The trick, new computer simulations show, is heat released by the planetary embryos themselves, triggering tidal forces in the surrounding gas and dust that offset the sun’s gravitational pull.
Previous computer models didn't take tidal effects into consideration, astronomer Frederic Masset, with the National Autonomous University of Mexico, wrote in an email to Discovery News.
That idea stemmed from a realization that similar processes drive the migration of stars in compact regions at the center of galaxies.
“A few years ago, after I gave a seminar at the University of Texas at Austin, I was asked by one of the researchers in the audience whether the luminosity of the stars in an AGN (Active Galactic Nuclei) could alter their migration.
“I initially thought that this would have no effect, but I realized afterward that tiny asymmetries in the heated disk in the immediate vicinity of the planet (or star, in an AGN) could potentially have huge effects on the tidal force. This is why I eventually decided to investigate the role that the heating due to planetesimal bombardment could have on planetary migration,” Masset said.
The research brings computer models closer to explaining what is observed in the solar system and a roadmap for understanding planetary development around other stars.
Read more at Discovery News
Mar 31, 2015
Video of the animal (see below) shows an eerily human-contoured face, with a prominent nose, broad mouth, and a chin Jay Leno might admire.
A veterinarian in the village attributed the deformity to an excess of Vitamin A in the mother's diet, the Irish Mirror reported.
According to the site, Lavrentiev said: "Whatever has caused it she’s a little beauty and I definitely won’t be selling her for anyone’s dinner table either as the buyers want her on display."
From Discovery News
After a two year hiatus for a significant power upgrade, it was hoped that the LHC would start circulating particle beams last week. Unfortunately, an electrical short delayed the restart, prompting fears that the delay could suspend operations for weeks or even months while a solution was found.
But after troubleshooting the issue, a small piece of metal debris was found in a diode box — a component of the electromagnet’s safety system — triggering a short with the magnet’s power supply. The debris originated from the upgrade work.
According to Nature News, on Monday, engineers sent an electrical discharge through the problem circuit, burning away the metal debris.
“It’s a bit like deliberately blowing a fuse,” said Paul Collier, head of beams at CERN.
Today, after tests, engineers report that the fix has worked and now the short has cleared. There’s some more work that needs to be done before they can re-power the circuit again, but things are looking up. “We hope to be ready to take beam sometime during the weekend,” added Collier.
Sending an electrical discharge through the problem circuit prevented the need to to warm up the cryogenic magnet and cool it back down again to 1.9 Kelvin (just above absolute zero) after the debris was manually removed. Such a procedure would have caused a lengthy delay.
Now we can start getting (re-)excited for the grand restart, kicking off the second run of the biggest and most powerful particle accelerator on the planet.
Run 2 will see proton beams blasting around the LHC at an energy of 6.5 TeV — providing collision energies of a whopping 13 TeV, nearly double the collision energy of the LHC’s first run. We are about to cross the threshold into a new regime for physics where there are high hopes for answering some of the biggest mysteries in modern science, including the origin of dark matter and the possibility of micro-black holes.
Read more at Discovery News
“We changed how the rover uses flash memory in an attempt to correct problems the rover had been experiencing,” said John Callas, project manager for Opportunity at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., in a news release “Although we are a little disappointed at the occurrence of an amnesia event only five days after reformatting, we are not surprised. There is still no clear understanding of what is causing the problems. Only time will tell if we have been successful in mitigating the most serious flash problems.”
The problem was thought to be centered around one of the seven memory banks in Opportunity’s flash memory — the rover’s on board “hard drive” of sorts, where data can be stored even if the rover is powered down. Rather than being lost, mission telemetry can be stored when the rover is switched off to preserve battery life during the Martian nights.
But late last year, the rover would “forget” valuable data, caused by a corrupt flash data bank. As a consequence, random resets would occur throughout the day. This was hindering the mission’s progress, prompting mission engineers to adopt a “no-flash mode” where Opportunity would avoid use of its flash memory, instead temporarily storing data to its volatile memory and regularly transmitting the data back to Earth before downtime.
Like the RAM on your PC or Mac, the volatile memory only provides temporary storage of data, becoming wiped when the rover powers down.
After uploading new software to avoid the use of the 7th flash memory bank, on March 20, engineers reformatted Opportunity’s memory. Although the rover isn’t currently exhibiting some of the worst symptoms associated with the amnesia, it appears that its memory problems are far from over.
From Discovery News
The left image shows Rhea (that’s pronounced REE-ah) from a distance of about 51,200 to 46,600 miles (82,100–74,600 km) and the right is a bit closer, made of images captured from about 36,000 to 32,100 miles (57,900–51,700 km). The entire image was assembled by Heike Rosenberg and Tilmann Denk at Freie Universität in Berlin, Germany.
The images were acquired during T-109, a targeted flyby of Titan.
Rhea is Saturn’s second-largest moon after Titan, but at 950 miles (1,530 km) across Rhea is less than a third of its larger sibling’s diameter. Its high reflectivity is a result of being mainly composed of water ice, which is harder than rock at Rhea’s frigid surface temperatures of -300 degrees Fahrenheit (-185 degrees Celsius).
Rhea is also extensively fractured and cratered. In fact it’s one of the most — if not the most — heavily-cratered worlds in the entire solar system, a hallmark of an extremely ancient surface.
But Cassini won’t last forever. Over the next two and a half years the spacecraft will exhaust its last reserves of fuel and, in order to avoid any unwanted collision with Saturn’s moons, will go out in a blaze of glory with a final dive inside the rings and into Saturn’s atmosphere.
Before that happens Cassini will continue its exploration of Saturn’s moons, making a few more passes this year of Titan, Dione, and Enceladus — the latter of which we now know (thanks to Cassini) almost certainly possesses a deep subsurface ocean of salty liquid water.
Read more at Discovery News
Mar 30, 2015
The skin of the box-patterned gecko (Lucasium sp.) is able to prevent the adhesion of everything from household liquids to dirt and bacteria, according to new research. The skin also exhibited self-cleaning properties.
This discovery may have important implications for the design of medical implants, self-cleaning hospital surfaces and even water filters.
"Gecko skin is very thin -- only a few microns deep -- and they live in a hostile environment where bacteria can flourish, so we wondered what other protective measures the skin might confer," says Dr Greg Watson from the University of the Sunshine Coast, one of the leaders of the international team who undertook the research.
They found that the skin of the gecko consists of dome-shaped scales that are made up of super-tiny spinules -- or hairs -- ranging in size from several hundred nanometres to several microns in length.
When the researchers tested the skin's response to a range of contaminants such as pollen and dust, they found that they just didn't stick.
"The skin's topography provides a super-hydrophobic, anti-wetting layer that allows droplets as small as those found in fog to roll and even jump off the peaks and through the valleys in the skin, taking dirt, pollen and other contaminants with them," Watson explains.
Their study is published in Acta Biomaterialia.
Box-patterned geckos are found in the semi-arid Mingela Ranges in Western Queensland.
"The geckos are small, which means they have a high surface area to volume ratio, that is they have a lot of skin relative to their body mass," Watson says.
Watson and team also found that gecko skin shares many of the same structural properties as cicada wings, which are known to repel water and contaminants.
When the researchers placed Porphyromonas gingivalis, the bacteria that causes gingivtus and periodontal disease, on the gecko skin they found that most were killed within less than a day, without any application of chemicals.
Watson says that while they are not certain of what killed the bacteria, it is possible that they were impaled on the skin's spiny surface.
"However when human stem cells (from tooth pulp) were applied to the skin surface, they grew happily."
He says that stem cells are much larger than bacteria, which may explain why they were able to withstand the impact of the spines.
Read more at Discovery News
Excavation director Diego Barkan said 17 pits were found that had been used to store produce in the Early Bronze Age, from 3500 to 3000 BC.
"Among the hundreds of pottery sherds that characterize the local culture, a number of fragments of large ceramic basins were discovered that were made in an Egyptian tradition and were used to prepare beer," he said in a statement.
The excavation is the first to offer evidence of an "Egyptian occupation" in the center of Tel Aviv 5,000 years ago.
"This is also the northernmost evidence we have of an Egyptian presence in the early Bronze Age," he said.
According to the antiquities authority "beer was the Egyptian national drink and was a staple along with bread."
It said beer was consumed by the entire population of Egypt, regardless of age, gender or status.
"It was made from a mixture of barley and water that was partially baked and then left to ferment in the sun. Various fruit concentrates were added to this mixture in order to flavor the beer," the statement added.
Previous excavations carried out in Egypt's Delta region uncovered breweries that indicate beer was already being produced in the mid-fourth millennium BC, the Israeli authority said.
From Discovery News
Black hole mergers are thought to be the most energetic events the universe has seen since the Big Bang, nearly 14 billion years ago. These events are occur when two (or more) spinning black holes become trapped in their mutual gravitational wells, orbit and then collide, merging as one. The energy generated in these merging events are thought to create a very specific signature of gravitational wave emissions.
According to Einstein’s theory of general relativity, gravitational waves should be created when massive objects accelerate through space. However, they have not been directly observed. Indirectly, we can see their impact when white dwarf binaries, for example, orbit one another — over time, as their orbits shrink, energy is lost. This energy must be carried away from the system by gravitational waves.
Although we have a pretty good idea about their properties, gravitational waves are notoriously difficult to detect directly, but should they become detectable in the future, a new era of gravitational astronomy may be possible. And black hole mergers could be the key to making this happen.
“An accelerating charge, like an electron, produces electromagnetic radiation, including visible light waves,” Michael Kesden, of the University of Texas at Dallas, said in a press release. “Similarly, any time you have an accelerating mass, you can produce gravitational waves.”
Kesden is the lead author of new research into black hole mergers published in the journal Physical Review Letters.
“Using gravitational waves as an observational tool, you could learn about the characteristics of the black holes that were emitting those waves billions of years ago, information such as their masses and mass ratios, and the way they formed,” added co-author Davide Gerosa, of the University of Cambridge, UK. “That’s important data for more fully understanding the evolution and nature of the universe.”
Currently, there are several projects underway that are attempting to detect gravitational waves. Perhaps the most famous detector is the Laser Interferometer Gravitational-Wave Observatory (LIGO) situated at two locations in the US — in Louisiana and Washington. LIGO is set up to detect the passage of gravitational waves through our local volume of space.
Using precision lasers along two 4 kilometer-long tunnels in “L” shaped structures, the very slight perturbations of spacetime should be detectable as gravitational waves pass through our planet. Although LIGO has yet to detect a positive gravitational wave signal, it is currently undergoing upgrades that will boost its sensitivity. “Advanced LIGO” is scheduled to go online later this year. Europe is also building its own detector called VIRGO and the LISA Pathfinder Mission is planned to set up a gravitational wave detector in space.
“The equations that we solved will help predict the characteristics of the gravitational waves that LIGO would expect to see from binary black hole mergers,” said co-author Ulrich Sperhake, also of the University of Cambridge. “We’re looking forward to comparing our solutions to the data that LIGO collects.”
The researchers have specifically focused on modelling the spin and precession of binary black holes as they orbit one another.
“Like a spinning top, black hole binaries change their direction of rotation over time, a phenomenon known as procession,” said Sperhake. “The behavior of these black hole spins is a key part of understanding their evolution.”
“With these solutions, we can create computer simulations that follow black hole evolution over billions of years,” said Kesden. “A simulation that previously would have taken years can now be done in seconds. But it’s not just faster. There are things that we can learn from these simulations that we just couldn’t learn any other way.”
Read more at Discovery News
A new project called the Hunt for Exomoons with Kepler (HEK) is the first systematic search for exomoons, or moons that circle planets outside our solar system. HEK astronomers, led by David Kipping at the Harvard-Smithsonian Center for Astrophysics, simulate billions of possible star-planet-moon arrangements using NASA's Pleiades Supercomputer.
They then compare the results with actual data taken with NASA's Kepler telescope, which monitors the brightness of stars in an effort to find exoplanets that could harbor life. If one of the simulated combinations matches the Kepler data, that area warrants further exploration.
So far, the team has surveyed 56 of about 400 Kepler planet candidates that could have an exomoon. Surveying the remaining 340 would require 50,000 processing hours per object and nearly a decade on a smaller computer.
The Pleiades Supercomputer, which performs over 3 quadrillion calculations per second, knocks that number down to 30,000 processing hours per object and should complete the project in two years.
"For each planet where we don't discover an exomoon, we are able to say how massive a moon is excluded by the current data, telling us about our sensitivity," Kipping said in a statement.
HEK scientists compare the exomoons they're searching for to the moon Pandora in Avatar. But unlike a science-fiction film that depicts complicated and evolved societies, astronomers say signs of life on an exomoon could be as simple as "some form of primitive biology."
Read more at Discovery News
Mar 29, 2015
Researchers going back to Charles Darwin have focused on the contrast between the sexes, attributing the males' brighter colors to their need to attract mates.
A group of researchers at University of Wisconsin-Milwaukee took a different approach, testing a hypothesis that evolution has actually resulted in similarities among the sexes as much as differences.
Looking at nearly 1,000 species of birds, they found that while males often have brighter feathers than females, the two sexes have come closer together in color over time to blend into their surroundings and hide from predators. Natural selection -- during migration, breeding in subtropical locales and care of young -- is as powerful as sexual selection.
"Although most studies of bird plumage focus on dichromatism, evolutionary change has most often led to similar, rather than different, plumage in males and females," the authors write.
Peter Dunn and Linda Whittingham, professors of behavioral ecology at UW-Milwaukee, wrote the paper with Jessica Armenta, a former UW-Milwaukee graduate student who now teaches at Austin Community College in Texas.
"Our study shows that ecology and behavior are driving the color of both sexes, and it is not due to sexual selection," they write.
The paper, "Natural and sexual selection act on different axes of variation in avian plumage color," is being published in Science Advances.
Armenta spent four years collecting data from 977 species of birds from six museums in the U.S. and Australia. She looked at six birds of each species, three males and three females.
Dunn and Whittingham analyzed the data, assigning each bird a color score based on scales of brightness and hue. They examined plumage color in relation to 10 measures of natural and sexual selection.
"Researchers have called for separate analyses of each sex for over a decade, but this is the first large-scale study to examine the color of each sex in relation to indices of both natural and sexual selection," they write.
When the sexes became more similar in color, they did so for reasons of natural selection. When the color gap increased, it had more to do with sexual selection, they found.
Dunn hopes the findings will send future research in new directions.
"A lot of research has focused on how plumage color is related to mating success, especially in males," he says, "so this should hopefully get researchers to think more about how color affects survival, especially predation and foraging success, in both sexes."
Within the larger findings is another surprise: male birds with multiple mates actually tend to be duller in color than their female counterparts.
Male red-winged blackbirds, for example, can have up to a dozen mates but are less colorful than their consorts.
"The reason for this is that males in these species often have a lot of black plumage," Dunn says.
From Science Daily
The Neanderthals (Homo neanderthalensis) inhabited Europe and parts of western Asia between 230,000 and 28,000 years ago; during the last few millennia they coincided with Homo Sapiens Sapiens, and became extinct for reasons that are still being challenged. The archaeological site at La Ferrassie, excavated throughout the 20th century, is a mythical enclave because it was where 7 Neanderthal skeletons, ranging from foetuses to almost complete skeletons of adults, were found.
Among the remains discovered at La Ferrassie is the skeleton of a 2-year-old Neanderthal child found between 1970 and 1973 and baptised La Ferrassie 8; over 40 years since its discovery it has turned out to be useful in shedding new light on the anatomy of this extinct species.
The study began by reviewing the collections at the Muséum National d'Histoire Naturelle in Paris and at the Museo d'Archéologie national de St. Germain-en-Laye linked to the excavations at La Ferrassie in 1970 and 1973; it was there that 47 new fossils belonging to La Ferrassie 8, which complete its skeleton further, were recovered. Remains of a skull, jaw, vertebrae, ribs and hand phalanges were found among the new fossils.
Featuring among the remains is a very complete left temporal bone and an auditory ossicle was found inside it: a complete stapes. Virtual 3D reconstruction techniques enabled this ossicle to be "extracted virtually" and studied.
This stapes is the most complete one in the Neanderthal record and certifies that there are morphological differences between our species and the Neanderthals even in the smallest ossicles in the human body. As Asier Gómez-Olivencia pointed out, "we do not yet know the relation between these morphological differences and hearing in the Neanderthals. This would constitute a new challenge for the future."
The study of these new remains has been published in the Journal of Human Evolution, and has also had the participation of researchers of the CNRS (French National Centre for Scientific Research) in Paris and Bordeaux. The fact that a discovery of such significance has been made thanks to reviewing the remains excavated in the 1970s provides the researcher with proof of "the importance and need to review old excavations. We're in no doubt about that."
Asier Gómez-Olivencia, a doctor in Human Palaeontology, did research at the University of Cambridge and at the Muséum National d'Histoire Naturelle in France, until 2014 when he joined the UPV/EHU's Department of Stratigraphy and Palaeontology as an Ikerbasque Research Fellow.
From Science Daily