Feb 11, 2017
Archaeologists discovered the ancient tomb, which dates to the Comala Period (between 0 and A.D. 500), during work to remodel a Seventh-day Adventist church in Colima, Mexico. The archaeologists uncovered a hole that was sealed up with stones, artifacts for grinding, and human bones.
Inside, 12 skulls and other bones were piled atop one another in a haphazard manner. Some of the skulls showed signs of damage, as well as tooth fractures and wear, said Rosa María Flores Ramírez, a physical anthropologist at the National Institute of Anthropology and History (INAH) in Mexico.
When the archaeologists explored further, they discovered three burial levels. In the second burial level, the team found two figurines — a male and female — placed facedown next to two skulls.
The male figurine, which measures 15 inches (39 centimeters) tall and 6 inches (15 cm) wide, was wearing a feathered headdress with a horn jutting out from it. In his hand, he holds an ax.
The female figurine, which is 12.5 inches by 5.5 inches (32 by 14 cm), shows a woman with a sharp nose and a triangular head. She wears a banded headdress and has her hands crossed, with the right hand holding a pot. The burial also contained two other pots.
Each of the figures was sculpted from fine paste that was polished when complete. The ancient artists used cuts to etch in the facial features.
"The presence of these pieces in the offering hint at the worldview of the groups that inhabited the Colima valley in that period. The sculptures, according to their attributes, served as propitiatory elements that ensured the protection of the deceased, as is the case with the male sculpture, which represents a shaman. The other objects fulfilled the function of bringing the requirements to the underworld," Rafael Platas Ruíz, an archaeologist at the INAH, said in a translated statement.
Read more at Discovery News
The tomb, originally unearthed in 2011 on the Ardnamurchan peninsula in western Scotland, contained a rich assemblage of grave goods. It represents the first undisturbed Viking boat burial found on the British mainland.
Viking boat burials have been documented in Scandinavian countries, but are fairly rare. They involve using the boat as a coffin for the body. Archaeologists estimate the boat used to bury the deceased dates back to the late 9th or early 10th century, at a time when Vikings were still exploring and trading along the British Isles.
An in-depth investigation, published in the journal Antiquity, has revealed much of the Viking funerary rite involved in the burial at this remote part of Scotland. However, some mystery remains.
The ship rotted into the soil long ago, like the bones of the interred individual. Only two teeth (both molars) remain of the human. The absence of a body which researchers can biologically sex, might raise the compelling, albeit remote, possibility that it was a female boat grave.
"The burial is probably that of a man — but as we only have the two teeth surviving, it is impossible to be definitive. So it is possible, but not likely, that this was the burial of a woman," Oliver Harris, co-director of the Ardnamurchan Transitions Project (ATP) at the University of Leicester's School of Archaeology and Ancient History, told Seeker.
The funerary rite began with cutting a boat-shaped depression into a natural mound of small, rounded beach stones. The boat was then inserted and the body was placed inside, surrounded by a variety of artifacts including a sword, an axe, a drinking horn vessel, a shield boss, a ladle, a sickle and a ringed pin.
"There is nothing female per se in the grave, though of course there are lots of objects — sickle, the ladle, the knife, the ringed pin — that are not male either," Harris said.
|Some finds recovered from the grave (clockwise from the top left): broad-bladed axe, shield boss, ringed pin and hammer and tongs.|
"The final artifacts found in the boat, the spear and shield boss, were higher in the burial, deposited as part of the closure of the monument," the researchers wrote.
The spearhead was deliberately broken before being deposited, indicating some form of ritual associated with the burial process.
The archaeologists also recovered 213 of the boat's rivets. From the the outline of the boat impressed into the soil, they established the boat measured 16 feet in length and would have been a small rowing boat, probably accompanying a larger ship.
Isotopic analysis of the teeth suggests the deceased likely grew up in Scandinavia. It also showed that between the age of 3 and 5 the person's diet switched for about a year from meat to fish, an unusual food supply at that time.
"The switch in diet probably shows there was some shortage in food for a period of time leading people to eat more fish," Harris said.
Most importantly, the Viking boat burial reveals the growing relationship between Scotland and the Viking world at that time.
|Only two teeth, both molars, remain of the interred individual.|
"The burial evokes the mundane and the exotic, past and present, as well as local, national and international identities," the researchers wrote.
According to Colleen Batey, Senior Lecturer in Archaeology, University of Glasgow, the grave goods within the find are very significant.
"A sword with shield boss, spearhead and axe are a complete weapon set — which is not so common. And the ladle is an exceptional and uncommon find," she told Seeker.
Read more at Discovery News
Feb 9, 2017
The discovery is considered a key piece of evidence for a critical, but poorly understood period of time when the universe switched from being dark to radiating light.
Scientists theorize that energy from first-generation galaxies transformed the dark, electrically neutral universe into ionized and radiating plasma. But these faint galaxies are not easy to find.
This week, University of Texas astronomer Rachael Livermore and colleagues describe a successful hunt thanks to a new technique that combines deep-field Hubble Space Telescope images with what is known as "wavelet decomposition" — a light-masking equivalent of noise-canceling headphones — to computationally remove light from foreground galaxy clusters.
"The wavelet transform allows us to decompose an image into its components on different physical scales. Thus, we can isolate structures on large scales… and remove them, allowing objects on smaller scales to be identified more easily," the scientists wrote in a draft of their upcoming paper, published on arXiv.org.
|The MACS 0416 galaxy cluster as seen by Hubble as part of the Frontier Fields project|
By then masking the light, Livermore, University of Texas astronomer Steven Finkelstein and Space Telescope Science Institute astronomer Jennifer Lotz found 167 galaxies that are 10 times fainter than any previously known, a number that shows "strong support" for how many early galaxies would have been needed to re-ionize the universe.
A more direct detection method will come after Hubble's successor, the James Webb Space Telescope, is launched next year.
From Discovery News
And for a huge comet orbiting a white dwarf star some 170 light-years away, that doom has arrived in dramatic fashion.
While surveying the chemical makeup of white dwarf stars, astronomers using the Hubble Space Telescope and W. M. Keck Observatory noticed something peculiar about WD 1425+540. The star, located in the constellation of Boötes, has a polluted atmosphere containing carbon, oxygen, sulfur and, strangely, nitrogen.
Spectroscopic analysis of the white dwarf's starlight revealed that a massive comet, with a similar chemical composition as the solar system's Halley's Comet, must have undergone the mother of tidal disruption events, ultimately getting ripped to shreds, spreading its debris throughout the star's atmosphere. But this comet was 100,000 times more massive than Halley and appeared to have twice the proportion of water.
Although other white dwarfs have been observed ripping up rocky debris like asteroids and planets in the past, this one is special — it's the first time comet debris containing nitrogen, an element essential for life, has been spotted polluting a white dwarf's atmosphere.
"Nitrogen is a very important element for life as we know it," said Siyi Xu, of the European Southern Observatory in Germany, in a statement. "This particular object is quite rich in nitrogen, more so than any object observed in our solar system."
White dwarfs are the stellar remains of sun-like stars that have lived out their lives and died. Our sun, in another 4-5 billion years will run out of hydrogen fuel in its core and will start to fuse heavier elements. This will result in the sun puffing up into a huge red giant, swelling so wide that it will swallow Mercury and Venus, and possibly even Earth. Violent stellar winds will rip the outer layers apart, creating a vast planetary nebula. In the nebula's core will be a tiny, brightly shining clump of degenerate matter called a white dwarf — a star that's only the size of Earth, but 200,000 times more massive.
As our white dwarf sun will be so small with an incredibly high density, it will possess strong tides — if a planet, asteroid or comet comes too close, these tides will literally rip any celestial body apart, sprinkling the debris over its upper layers, leaving a telltale spectroscopic signature showing that it used to have a planetary system in tow. And the fact that comets appear to be actively falling into WD 1425+540's atmosphere reveals the star system has a Kuiper Belt-like feature that survived the red giant phase of its star.
Read more at Discovery News
A team from the Polytechnic University of Turin will scan the tomb and its surroundings with advanced radar technology.
"It will be a rigorous scientific work and will last several days, if not weeks," Franco Porcelli, the project's director and a professor of physics at the department of applied science and technology of the Polytechnic University in Turin, told Seeker. "Three radar systems will be used and frequencies from 200 Mhz to 2 GHz will be covered."
The investigation of King Tut's tomb is part of a wider long-term project to conduct a complete geophysical mapping of the Valley of the Kings, the main burial site of Egypt's pharaohs, which is also being led by the group from the Polytechnic University of Turin.
Ground-penetrating radar, together with instruments based on electric resistance tomography and magnetic induction, will scan depths of up to 32 feet to provide information on existing underground structures.
"Who knows what we might find as we scan the ground," Porcelli remarked.
The researchers plan to carry out the first preliminary survey of King Tut's tomb by the end of this month.
Porcelli's probe into the 3,300-year-old burial will be the third carried out in the past two years.
The search began in 2015 following a claim by Nicholas Reeves, a British Egyptologist at the University of Arizona. Reeves believes there is a hidden chamber in King Tut's tomb that contain the remains, and possibly the intact grave goods, of Queen Nefertiti, wife of the "heretic" monotheistic pharaoh Akhenaten, Tutankhamun's father.
Reeves speculated that the tomb of King Tut was not ready when the pharaoh died unexpectedly at age 19 in 1323 B.C. Consequently, he was buried in a rush in what was originally the tomb of Nefertiti, who had died 10 years earlier.
Radar scans carried out in 2015 by Japanese radar specialist Hirokatsu Watanabu were greeted with enthusiasm by Mamdouh Eldamaty, Egypt's former minister of antiquity.
He revealed that analysis of Watanabu' scans pointed to a "90 percent chance" that King Tut's tomb concealed two chambers, on the north and eastern walls.
The announcement sent shock waves through the world of archaeology.
"This could be the discovery of the century," Eldamaty said.
But a follow-up radar scan carried out by the National Geographical Society (NGS) cooled down expectations as it failed to replicate Watanabu's compelling results.
The theory that King Tut's tomb contains secret chambers was greeted with great skepticism last year at an international conference in Cairo dedicated to the boy king.
"The project wasn't done scientifically at all," former Antiquities Minister Zahi Hawass said at the conference.
Growing doubts about Reeves' tomb theory prompted the current Egyptian antiquities minister Khaled El-Enany to reassure that no invasive exploration inside the tomb would be done.
Read more at Discovery News
Researchers said Wednesday the slip and vast debris field of large blocks, or knolls, at its edge reveals a far more complex reef landscape than was previously known.
"In an area of the Queensland Trough that was supposed to be relatively flat were eight knolls, appearing like hills with some over 100 [feet] high and [nearly 3 miles] long," Dr. Robin Beaman, from James Cook University, said.
Remnants of the slip, known as the Gloria Knolls Slide, were first found in 2007 while scientists were carrying out three-dimensional mapping of the Queensland Trough, a deep basin that runs adjacent to the reef.
After finding the knolls poking up from the sea floor, scientists spent years mapping the area to find the landslide that caused the underwater hills, which are located about 47 miles offshore at a depth of between 4,000 to 4,600 feet.
A sediment sample from the largest knoll, taken at a depth of about 4,000 feet, revealed the presence of a cold-water coral community which allowed researchers to date the event.
"The oldest fossil corals recovered off the top of the knoll were 302,000 years old — which means the landslide event that caused these knolls must be older," lead researcher Dr. Angel Puga-Bernabéu, a former postdoctoral researcher from the University of Sydney who is now with the University of Granada, said in a statement.
The landslide was a "catastrophic collapse" that pushed debris about 20 miles from the base of the slip, Beaman said.
Modeling also showed a potential tsunami wave of up to 30 feet high. However, the wave's impact would likely have been dampened by the vast coral reef system, researchers said.
The findings, published in the journal Marine Geology, shed new light on the deepest reaches of the Great Barrier Reef, the world's largest coral reef ecosystem.
"Prior to 2007 we just didn't know what the deep Great Barrier Reef landscape looked like," Beaman said. "This is building up a far more detailed picture of how complex it is down there."
Already the team of international researchers have been surprised by the marine life they have found in the deep-sea conditions where temperatures can drop to 39 degrees Fahrenheit and it is pitch black.
"There was lot of marine life. We found both living and dead cold water corals," Beaman said. "They are very different to the shallow water cousins and don't rely on sun light at all."
|Westerly view of the Gloria Knolls lying in the Queensland Trough downslope of the Gloria Knolls Slide. Depths are colored red (shallow) to blue (deep), over a depth range of about 1500 meters.|
The Great Barrier Reef is one of the most biodiverse natural systems on earth and is home to about 1,400 coral reef species and 1,625 species of fish.
Samples taken from the deep water coral community included gorgonian sea whips, bamboo corals, molluscs and stalked barnacles.
Read more at Discovery News
Inside the cave, archaeologists found a blank scroll along with the remains of jars, cloth and a leather strap. The researchers said they believe these items were used to bind, wrap and hold the scrolls.
Between 1947 and 1956, the Dead Sea Scrolls were found in a series of 11 caves located near the site of Qumran in what is now the West Bank. The scrolls contain copies of books of the Hebrew Bible along with community rules, calendars and astronomical texts, among other writings.
Some of the scrolls were found by the Bedouin people, who sold the artifacts to antiquities dealers, while other scrolls were found during archaeological excavations. [See Images of the Dead Sea Scrolls]
Archaeologists taking part in the excavation said they could tell from modern day pickaxes found in the cave that the newly discovered cave had been robbed. Thus, any scrolls that may have held writing were taken, the researchers said. The scientists added that they think the blank scroll found in the cave was, in ancient times, being prepared for writing.
"Although, at the end of the day, no scroll was found, and instead we 'only' found a piece of parchment rolled up in a jug that was being processed for writing, the findings indicate beyond any doubt that the cave contained scrolls that were stolen," said excavation director Oren Gutfeld, an archaeologist at the Hebrew University's Institute of Archaeology, in a statement.
"The findings include the jars in which the scrolls and their covering were hidden, a leather strap for binding the scroll, a cloth that wrapped the scrolls, tendons and pieces of skin connecting fragments, and more," he added.
Some of the thousands of fragments of Dead Sea Scrolls that are now in museums or private collections could have come from this new cave rather than the 11 previously known caves, Gutfeld said. "Finding this additional scroll cave means we can no longer be certain that the original locations (Caves 1 through 11) attributed to the Dead Sea scrolls that reached the market via the Bedouins are accurate," Gutfeld said in the statement.
The excavation of the cave is part of a larger operation in which the Israel Antiquities Authority is trying to find and excavate caves in the Judean Desert that may hold archaeological remains. The operation was sparked by the activity of looters in the Judean desert.
Read more at Discovery News
Feb 8, 2017
Take this recent observation from NASA's Mars Reconnaissance Orbiter for example. From afar, a small cluster of dark blemishes on an otherwise pale landscape was the only indication of a meteorite impact, but on closer inspection, we realize it wasn't a single impact — it was in fact dozens all clustering around a small area in the Tharsis region of the Red Planet.
Initially detected by the orbiter's Mars Context Camera (CTX), scientists were able to determine that the impact must have occurred some time between 2008 and 2014. That detection led to a followup on Oct. 4, 2016, by the mission's High-Resolution Imaging Science Experiment (HiRISE) camera and the true nature of the impact became apparent. Two large impact craters accompanied by up to 30 smaller craters litter the scene, revealing that a meteoroid broke up in Mars' atmosphere, sending pieces of rock raining down onto the dusty surface.
The MRO regularly surveys for, studies and tracks long-term changes in fresh impact sites on Mars. These impacts not only tell us how frequent meteorite impacts are on Mars, they also provide a natural means to excavate material so we can see what minerals — that have not been exposed to the harsh weathering effects of being exposed on the Red Planet's surface — lie beneath. Also, by tracking long-term changes to the dusty material around the blast sites, we can learn something about surface winds and the movement of fine particles over time.
It is worth noting that the dark areas surrounding the impact sites isn't only ejecta that got blasted out of the crater. As the meteorites slammed into the ground, shocked air blew surface dust away, stripping the darker, fresh material bare around the crater. By analyzing the pattern of impact ejecta, planetary scientists are able to determine the direction from which the meteorites came from. In the above image, the meteoroid likely struck from the south (traveling from bottom to top).
|The MRO's Mars Context Camera view of the Tharsis region where the meteorite cluster was first detected|
As Mars' atmosphere is approximately 100 times thinner than Earth's, more meteors that streak through the atmosphere make it to the ground as meteorites. And in many cases, the atmosphere isn't quite thick enough to burn-up incoming space rocks, but thick enough to cause them to break up into many pieces. So rather than getting hit by a single projectile, depending on the size of the meteor, many bits of projectile can blanket bomb a large area.
Read more at Discovery News
Lybia leptochelis, also known as a boxer crab or a pom-pom crab, will fight over the sea anemones and then split the remaining ones in two. The split sea anemones will regenerate over the course of a few days. The crabs then wield the stinging predators as a means of self-defense or to stun prey.
Since the 19th century, scientists have noticed these funny little creatures, less than an 1 inch long (2.5 centimeters) lurking under boulders throughout the ocean. The creatures are easy to miss, with their sea anemones and tannish rock coloration acting as camouflage.
"Boxer crabs of the genus Lybia have the remarkable habit of carrying a sea anemone in each of its claws by means of delicate hooks, slightly embedded in the sea anemone column," the researchers wrote in the paper published today (Jan. 31) in the journal PeerJ.
As for what the sea anemones get out of the partnership, past studies found that these "kept" anemones have greater access to oxygen and food (leftover scraps from the crab), which helps them grow. However, it's a double-edged sword: "The crabs regulate the food intake of their sea anemones, and consequently control their growth, maintaining small, 'bonsai' sea anemones for their use," the researchers wrote, noting that they had found this behavior in their past studies.
However, researchers didn't know exactly how the crabs got their decorations. To figure that out, Yisrael Schnytzer, a graduate student at Bar Ilan University in Israel, and his colleagues tracked down more than 100 boxer crabs from the Red Sea. Amazingly, every crab — even the baby crabs — were found clutching two sea anemones from the genus Alicia.
Back at their lab, the researchers conducted a series of experiments on the collected crabs. In the first, they took away one anemone from each crab. They found the single-anemone crabs splitting the sea anemone into two, then waiting with pom poms in claw for the anemones to regenerate to their full size over several days. Thus, the crab was inducing asexual reproduction in the sea anemones, organisms that normally don't just split willy-nilly.
Read more at Discovery News
The light controlled by the fish (Anomalops katoptron), is so bright that it can illuminate and stun prey.
The findings, published in the journal PLOS ONE, help explain at least one purpose of the fish's light, which has long puzzled scientists, not to mention scuba divers and snorkelers who have been startled by the sight of the fish in its "on" mode. The light can be viewed from up to 100 feet away.
"I have observed Anomalops several times in the field and a thousand times in the lab and the luminescent light is definitely bright and impressive," Jens Hellinger, chair of the Department of Zoology and Neurobiology at Ruhr-University Bochum in Germany, told Seeker.
|Traces of light produced by a school of splitfin flashlight fish.|
When the fish blink, they "rotate the light organ backwards," Hellinger said, preventing each colony of bacteria from releasing visible light. When the light is on, he explains, "it is projected from the bean-shaped light organs under the eyes and not from the eyes."
Fascinated by the ability, Hellinger and his team studied the fish on moonless nights in waters off the Banda Islands of Indonesia. The fish are popular with aquarium enthusiasts, so the researchers also obtained a school of them from a commercial wholesaler and studied the fish back at their lab.
They found that during the darkness of night, the flashlight fish blink very frequently, at 90 blinks per minute. This causes their light to go on and off for an equal amount of time.
|School of splitfin flashlight fish.|
Read more at Discovery News
The "Jupiter as a shield" concept arose from a misinterpretation of a 1994 paper by George Wetherill — a planetary scientist at the Carnegie Institution who died in 2006 — says planetary scientist Kevin Grazier. Wetherill's paper argued that systems with "failed Jupiters" (that is, star systems only with planets of perhaps Uranus and Neptune's size or smaller) would have more densely populated cometary source regions, and that they "eject a smaller number of comets into interstellar space."
Grazier, of NASA's Jet Propulsion Laboratory who has also served as an advisor for "Battlestar: Galactica" and "Gravity," told Seeker that he tried to replicate Wetherill's work from 1994. The aim was to see what had changed with the more advanced computing power of today.
"You see [Jupiter's influence] recreated all the time in documentary TV shows," Grazier said. He reasoned that Saturn is a large planet, too. "I just thought about that [theory] and I said, 'I don't believe that for a moment.'"
Grazier found that, through simulations, a typical small body — like an asteroid or comet — between Jupiter and Saturn will get kicked out, but many of them are ejected after they pass into the inner solar system. Further simulations (some dropping Jupiter from the equations, and some dropping Saturn) show that it takes both planets combined to reliably move objects out of the solar system. If only one planet of the two exists, a belt of material is created and only a few small bodies are removed from the solar system.
Read more at Discovery News
Feb 7, 2017
When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth's atmosphere. Because carbon in the air is absorbed by trees, carbon-14 levels in tree rings actually reflect solar activity and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.
"We measured the 14C levels in the pine sample at three different laboratories in Japan, the US, and Switzerland, to ensure the reliability of our results," A. J. Timothy Jull of the University of Arizona says. "We found a change in 14C that was more abrupt than any found previously, except for cosmic ray events in AD 775 and AD 994, and our use of annual data rather than data for each decade allowed us to pinpoint exactly when this occurred."
The team attempted to develop an explanation for the anomalous solar activity data by comparing the features of the 14C change with those of other solar events known to have occurred over the last couple of millennia.
"Although this newly discovered event is more dramatic than others found to date, comparisons of the 14C data among them can help us to work out what happened to the sun at this time," Fusa Miyake of Nagoya University says. She adds, "We think that a change in the magnetic activity of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data."
Read more at Science Daily
The large geometric, ditched enclosures had long remained hidden by trees. But modern deforestation, in combination with Google Earth technology, have now revealed the presence of the more than 450 geoglyphs.
The carved ditches measure up to 36 feet wide, 13 feet deep and are 300 to 1,000 feet in diameter. The features "rival the most impressive examples of pre-Columbian monumental architecture anywhere in the Americas," Jennifer Watling, a post-doctoral researcher at the Museum of Archaeology and Ethnography at the University of Sao Paolo, and colleagues wrote in the journal Proceedings of the National Academy of Sciences.
Excavations of the geoglyphs, which show a highly formalized architecture made of geometrical circles and squares, suggest they were used occasionally as public gathering sites to carry out ritual or ceremonial activities some 2,000 years ago.
The outer ditch and inner wall enclosure of the geoglyphs identify them as henge sites similar to Stonehenge, which is around 2,500 years older.
"We are still a long way from answering what the enclosures meant to the geoglyph builders themselves," Watling told Seeker. However Watling added, "We are quite sure that they were not sites of permanent villages, nor defensive structures, due to both the forms of the earthworks and the small quantity of cultural remains that we discover when excavating them."
Indeed, the almost complete lack of cultural material within the geoglyph area, suggests the enclosures were kept ritually "clean."
The discovery of the huge earthworks has significant implications, not only for their puzzling meaning, but also because it overturns the notion of Amazonian rainforests as a pristine wilderness.
"We immediately wanted to know whether the region was already forested when the geoglyphs were built, and to what extent people impacted the landscape to build these earthworks, " Watling said.
Watling, who was working toward her PhD at the University of Exeter at the time the research was carried out, and her colleagues dug soil samples from holes five feet deep within and outside two geoglyph sites.
|The geoglyphs show an highly formalized architecture made of geometrical circles and squares.|
To date the sites, which were dug at various times between the first and 15th centuries, the researchers used charcoal associated with artifacts found at the bottom of the ditches.
The team then analyzed the soil profiles for charcoal, which points to burning activity, and stable carbon isotopes, to provide an indicator of the dominant vegetation types present before, during and following construction of the geoglyphs.
The researchers also analyzed the samples for phytoliths, a type of microscopic plant fossil made of silica that helps identify ancient species. This allowed them to reconstruct millennia of vegetation and fire history around the two geoglyph sites.
It emerged that the bamboo forest ecosystem that exists in the region today was present throughout the past 6,000 years.
Read more at Discovery News
The new gecko, named Geckolepis megalepis and described in the journal PeerJ, has skin that is made up of unusually large scales. Consisting of keratin and bony calcium-rich components, the scales are at the heart of the gecko's defense system.
Birds, snakes and even other bigger geckos that try to eat Geckolepis often fail.
"A typical predator encounter might start with the predator trying to grasp the lizard in its jaws or claws, triggering the scale sloughing, which ideally lets the gecko escape denuded but alive," lead author Mark Scherz told Seeker.
|Denuded Geckolepis megalepis.|
Three-dimensional X-rays of the geckos, which are a type of lizard, enabled Scherz and his team to analyze Geckolepis' anatomy in detail, including its scales. Other geckos are able to lose their skin when predators grab them, but the newly discovered gecko can do this at the slightest touch.
In fact, when Scherz went to capture a few individuals for the study in Marojejy National Park of northeast Madagascar, it took him several, challenging tries.
The gecko would obviously rather not be bothered, especially as it is very costly for the lizard to regrow its scaly skin. But, as Sherz said, at least doing so "is much less costly than being eaten."
When the gecko heals up, it does so scar-free.
"The fact that the regeneration is, at least superficially, scar-less, gives us hope that some process in scale regeneration might have potential for implementation in scar-less healing in humans," Scherz said.
Read more at Discovery News
"The watery environments that once occupied the floor of Gale Crater look like they were pretty hospitable to life — not too hot, not too cold, not too acid, not too alkaline, and the water probably was not too salty," said study lead author Thomas Bristow, a planetary scientist at NASA's Ames Research Center in Moffett Field, California. [ Photos: Ancient Mars Lake Could Have Supported Life]Ancient Mars must have been much warmer than the planet is today for such environments to persist, many scientists think. As such, prior work sought to look for signs that Mars once possessed ample amounts of greenhouses gases such as carbon dioxide in its atmosphere, which trap heat from the sun.
However, analyses of data taken from orbit above Mars suggested little in the way of the carbonate minerals on the Martian surface that one would expect to find if its atmosphere were once richer in carbon dioxide. To help solve this mystery, scientists examined data collected from the Red Planet's surface by NASA's Curiosity rover as it traversed the lower slopes of the mountain Aeolis Mons (known informally as Mount Sharp), which rises about 3.4 miles (5.5 kilometers) high from the center of Gale Crater.
The researchers analyzed Martian mudstones, siltstones, sandstones and other sedimentary rocks deposited by lakes and rivers on the floor of Gale Crater about 3.5 billion years ago. They did not detect carbonates, suggesting that atmospheric levels of carbon dioxide back then were tens to hundreds of times lower than those required by climate models to warm early Mars enough to keep liquid water on its surface.
These findings do not suggest that ancient Mars wasn't wet, study team members said. "The sedimentary evidence at Gale Crater is indisputable in showing the prolonged presence of liquid water on the surface of early Mars," Bristow told Space.com.
One possible explanation for this discovery is that Mars once did have carbonates on its surface that were later destroyed. However, "the nature of the minerals in the samples we focused on don't support that conclusion," Bristow said. "They don't show any sign of suffering an acidic attack that could have dissolved any carbonates there in the past."
Another possibility is that early Mars was warmed by other greenhouse gases, such as sulfur dioxide, methane or nitrous oxide.
"The downside of all these other greenhouse gases is that they tend to be quite reactive, so when you put them in the atmosphere, they don't hang out an especially long time," Bristow said. "So the warming periods driven by those kinds of greenhouse gases are relatively short-lived, which is not consistent with observations from Gale Crater where we have evidence for lakes and rivers that persisted for hundreds of thousands or even millions of years."
Read more at Discovery News
Feb 6, 2017
In a study published Feb. 6 in the journal Nature Communications, Dr. Lanying Zeng and her team at Texas A&M AgriLife Research discovered how the lambda phage decides what actions to take in its host, the E. coli bacterium.
A phage is a virus that infects and replicates within a bacterium. Phages were first discovered about 100 years ago, but recently scientists have begun to study how they can be used to attack disease-causing bacteria, especially strains that have become more resistant to antibiotics.
So numerous and diverse are phages -- numbering into the billions, according to various reports in the U.S. National Library of Medicine -- that researchers are now hot on the trail of phages that have the potential for curing specific bacterial maladies.
The lambda phage, for example, prefers to destroy E. coli bacteria, which makes it a prime target for researchers. In tracking that target, Zeng's graduate student Jimmy Trinh developed a four-color fluorescence reporter system to track it at the single-virus level. This was combined with computational models devised by Dr. Gábor Balázsi, a biomedical engineer and collaborator at Stony Brook University in Stony Brook, New York, "to unravel both the interactions between phages and how individual phages determine" the fate of a cell.
What they found was not unlike the decision-making process of humans. Sometimes the lambda phage cooperates with others. Sometimes it competes.
"Instead of just the cell making a decision, we found the phage DNAs themselves also make decisions," Zeng said.
Through the process they developed, the scientists were able to determine that timing played a role in decision-making.
Zeng explained that some phages can have two cycles of reproduction: lytic and lysogenic.
In the lytic cycle, full copies of the virus are made inside of a cell, say an E. coli cell. When the phage-infected cell becomes full of the replicating viruses, it bursts open and is destroyed. In the lysogenic cycle, the phage's DNA lives as part of the bacterium itself and both continue to reproduce as one. In short, lysis involves competition while lysogeny involves cooperation, she said.
So, a key to using phages to destroy bacteria, Zeng said, is to understand how and when a phage decides to "go lytic" on the pathogen.
"Say you have two lambda phages that infect one cell," she said. "Each phage DNA within the cell is capable of making a decision. We want to know how they make a decision, whether one is more dominant than the other, whether they have any interactions and compete to see who will win, or whether they compromise."
"They may even coexist for some time and then finally choose one decision," she said. "But the phage is making a subcellular decision -- and that is very important. There could be a lot of implications."
The four-color fluorescence reporter system helped the researchers visualize that many factors contribute to the decision and that "from the evolutionary point of view, the phages want to optimize their own fitness or survival," she said. "So that is why they choose either lytic or lysogenic to maximize or optimize their survival."
Read more at Science Daily
|This is a close up of the radula preserved in Calvapilosa kroegeri next to a radula from a modern chiton.|
One of the defining characteristics of the molluscs is the possession of a radula, a kind of toothed-tongue which is used to rake up or rasp food.
The radula houses hundreds of teeth, the patterns of which can be used to determine diet and identify species. Whilst not all molluscs have a radula, a radula cannot be found in any other group of animals. Dr Jakob Vinther, from the Schools of Biological Sciences and Earth Sciences, is lead author of the study, which is published today in Nature.
He said: "The molluscs are amongst the earliest animals identifiable in the fossil record, however determining what their ancestor looked like is difficult since many of the groups appear within a small window of time, making the sequence of evolutionary events difficult to piece together."
The recent discovery of a new species of mollusc in the Anti-Atlas region in Morocco has enabled palaeontologists to revisit this problem and infer the appearance of the ancestor of all molluscs.
The new species discovered, Calvapilosa kroegeri, is part of the Fezouata Biota: a group of organisms from the early Ordovician period (485-470 million years ago) which are found in rocks in southeastern Morocco. The Fezouata Biota is famed for its exceptional preservation, allowing palaeontologists to identify details not preserved from any other fossil site.
Co-author Luke Parry, a PhD student at the University of Bristol, added: "Calvapilosa kroegeri resembles a slug covered with short spines all over its upper body and with a large 'fingernail-like shell' over its head. In the centre of the head of this species are two rows of teeth which we demonstrate is a radula."
The discovery of this feeding structure firmly identifies Calvapilosa kroegeri as a mollusc. Additionally, it suggests that similar fossil forms, such as Halkieria¬ -- a two plated slug-like fossil, are also molluscs and possessed a radula.
Following an analysis to determine the family tree of molluscs, Calvapilosa kroegeri was revealed to be the most primitive member of the lineage leading to chitons. Chitons can still be found today and are characterised by their possession of eight shell plates and spines around their margin, similar to what is seen covering the body of Calvapilosa.
Read more at Science Daily
Comet 45P/Honda-Mrkos-Pajdusakova (named after three astronomers who discovered it in 1948) travels into the inner solar system every 5.25 years. On Saturday, 45P will pass just 7.4 million miles from Earth, a stone's throw by celestial yardsticks.
With binoculars or a small telescope, comet-watchers should be able to spot 45P in the pre-dawn skies between Thursday and Sunday. "The comet will be racing through the constellation Hercules high in the eastern sky," notes SpaceWeather.com.
Comet 45P will look like fuzzy bluish-green ball with a fan-shaped tail. Its distinctive color comes from vaporizing diatomic carbon, a gas which glows green in the near-vacuum of space.
The Minor Planet Center reports 45P's upcoming pass as the eighth closest comet since modern tracking technologies began around 1950. It made an even closer approach during its last visit in 2011, pictured above, but it won't be as near to Earth again this century.
"Proximity makes the comet bright despite its small size," said SpaceWeather.com. "Forecasters say 45P could be on the verge of naked eye visibility… when it emerges into the pre-dawn sky later this week."
From Discovery News
The extreme warping of spacetime caused by the black hole's intense gravity creates powerful tides that will rip any stars and planets to shreds, but only before spaghettifying them into oblivion. Generally, though, if a star gets turned into Silly Putty by a black hole's tides, the suffering is a short-lived and explosive affair, where some of the star stuff gets consumed and the rest is ejected back out into space.
For one unfortunate star, however, a massive black hole has been seen mauling its stellar entrails for a decade — ten times longer than it usually takes for a black hole to finish a star meal — possibly revealing how the biggest black holes grew to be so massive.
"We have witnessed a star's spectacular and prolonged demise," said Dacheng Lin from the University of New Hampshire in Durham, New Hampshire. "Dozens of tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one."
By combining the observational power of three space telescopes — NASA's Chandra X-ray Observatory and Swift satellite, plus the European XMM-Newton — the drama has been seen unfolding in the center of a galaxy around 1.8 billion light-years away. Generating powerful X-rays, the tidal disruption event (TDE) — called XJ1500+0154 — has been telling astronomers the violent story of what happens when a star, roughly twice the mass of our sun, gets consumed by a supermassive black hole.
The event was first spotted by XMM-Newton July 23rd, 2005, and it reached peak brightness in a Chandra observation on June 5, 2008. Since then, the dimming X-ray emissions have been observed multiple times over the years, revealing a fascinating insight to how the most massive black holes consume matter and, perhaps, how they so quickly gained mass in the early universe.
By measuring the X-ray emissions, astronomers have been able to gauge how efficiently the black hole has been able to consume the blended stellar material collecting in the black hole's accretion disk. In this case, it appears the stellar material from this TDE is still being consumed and models suggest X-ray emissions from this particular event will continue to dim over the next few years.
"This event shows that black holes really can grow at extraordinarily high rates," said Stefanie Komossa of QianNan Normal University for Nationalities in Duyun City, China. "This may help understand how precocious black holes came to be."
Read more at Discovery News
The Australian pitcher plant (Cephallotus follicularis) and other carnivorous plants, described in the journal Nature Ecology and Evolution, appear to have independently evolved their carnivorous ways, but they all have certain traits in common. For example, they likely started with a craving for meat, which turns out not to be so different from a craving for fertilizer.
"What the carnivores [in this case, plants] are after is phosphorous and nitrogen: fertilizer," said Victor Albert, a biologist at the University of Buffalo. "The prey animals have this in abundance in the form of the proteins and nucleic acids that are released when the plant digests them."
"Many of the extant carnivorous plants and their ancestors have grown on nutrient-poor habitats, like acidic freshwater wetlands," helping to explain why they turned to eating meat, said Fukushima, who began the project when he was a graduate student. He's now a postdoctoral research fellow at the University of Colorado School of Medicine.
For the study, the researchers not only investigated the Australian pitcher plant, they also analyzed digestive fluids in three independently evolved pitcher plants and a sticky carnivorous plant, Drosera. Pitcher plants have deep cavities full of digestive fluid, while sticky meat-eating plants have leaves that are covered with goo. Like flypaper, the sticky leaves can then also trap insects.
Some carnivorous plants have also evolved clamshell-like snap mechanisms and even the ability to suck in prey underwater via suction traps.
The investigation found that although the various carnivorous plant lineages had split from a common ancestor more than 100 million years ago, each had repurposed genes, and their related proteins associated with stress response, to digesting meat.
Fukushima explained that many disease-fighting proteins in plants have the ability to break down basic cellular and extra-cellular components, such as a pathogen's protein, RNA and a fibrous substance called chitin.
"These compounds largely overlap with an insect's body components, and that might be one of the reasons why carnivorous plants were able to recruit pathogen-killing enzymes to carnivory," Fukushima said.
Read more at Discovery News