Sep 25, 2017

Genes are controlled by 'Nano footballs,' scientists discover

Rendering of DNA.
Research at the University of York has revealed that genes are controlled by 'nano footballs' -- structures that look like footballs but 10 million times smaller than the average ball.

By placing tiny glowing probes on transcription factors -- special chemicals inside cells which control whether a gene is switched 'on' or 'off' -- researchers gained a remarkable new insight into the way in which genes are controlled.

Crucially, they discovered that transcription factors operate not as single molecules as was previously thought, but as a spherical football-like cluster of around seven to ten molecules of roughly 30 nanometres in diameter.

The discovery of these nano footballs will not only help researchers understand more about the basic ways in which genes operate, but may also provide important insights into human health problems associated with a range of different genetic disorders, including cancer.

The research, supported by the Biotechnology and Biological Sciences Research Council (BBSRC) and published in eLife was carried out by scientists from the University of York, and the University of Gothenburg and Chalmers University of Technology, Sweden.

The researchers employed advanced super-resolution microscopy to look at the nano footballs in real time, using the same type of yeast cells utilised in baking and brewing beer.

Professor Mark Leake, Chair of Biological Physics at the University of York who led the work, said: "Our ability to see inside living cells, one molecule at a time, is simply breathtaking.

"We had no idea that we would discover that transcription factors operated in this clustered way. The textbooks all suggested that single molecules were used to switch genes on and off, not these crazy nano footballs that we observed."

The team believe the clustering process is due to an ingenious strategy of the cell to allow transcription factors to reach their target genes as quickly as possible.

Professor Leake said: "We found out that the size of these nano footballs is a remarkably close match to the gaps between DNA when it is scrunched up inside a cell. As the DNA inside a nucleus is really squeezed in, you get little gaps between separate strands of DNA which are like the mesh in a fishing net. The size of this mesh is really close to the size of the nano footballs we see.

"This means that nano footballs can roll along segments of DNA but then hop to another nearby segment. This allows the nano football to find the specific gene it controls much more quickly than if no nano hopping was possible. In other words, cells can respond as quickly as possible to signals from the outside, which is an enormous advantage in the fight for survival."

Genes are made from DNA, the so-called molecule of life. Since the discovery that DNA has a double helix shape, made in the 1950s by pioneering biophysics researchers, much has been learned about transcription factors which can control whether a gene is switched on or off.

If a gene is switched on, specialised molecular machinery in the cell reads off its genetic code and converts it into a single protein molecule.Thousands of different types of protein molecules can then be made, and when they interact that can drive the building of all of the remarkable structures found inside living cells.

The process of controlling which genes are switched on or off at any particular point in time is fundamental to all life. When it goes wrong, this can lead to serious health problems. In particular, dysfunctional switching of genes can result in cells which grow and divide uncontrollably, which can ultimately lead to cancer.

Read more at Science Daily

Ancient Egyptians Provided a Proper Burial to a Statue of a Revered Deity

Osiris statuette
After years of being washed, perfumed and fed in ancient Egypt, the statue of a revered Egyptian deity was given a proper burial with other "dead" statues more than 2,000 years ago, a new study finds.

Ancient Egyptians buried the statue of the deity Ptah — the god of craftsmen and sculptors — with other revered statues, including those of a sphinx, baboon, cat, Osiris, and Mut, in a pit next to Ptah's temple.

The statue of Ptah had likely sat in the temple for years, but it and the other sacred objects were respectfully buried after they accumulated damage and were declared useless by the ancient Egyptians, the researchers said.

"We can consider that when a new statue was erected in the temple, this one [of Ptah] was set aside in a pit," said study co-researcher Christophe Thiers, director of the French-Egyptian Center for the Study of the Temples of Karnak. "The other artifacts were also previously damaged during their ‘lifetime’ in the temple, and then they were buried with the Ptah statue."

Archaeologists discovered the pit in December 2014 at Karnak, an Egyptian temple precinct, and spent about a month excavating its rich assemblage. The pit held 38 objects, including:

Fourteen statuettes and figurines of Osiris.
Eleven fragments of inlay from statues.
The inlay included that of an iris, a cornea, a false beard, a cap, a strand of hair and an inlay plaque.
Three baboon statuettes (representing the god Thoth).
Two statuettes of the goddess Mut (one with hieroglyphic inscriptions).
Two unidentified statuette bases.
One head and one fragmentary statuette of a cat (Bastet).
One small fragmentary faience stele (a stone slab) recording the name of the god Ptah.
One head of a statuette of a man in gilded limestone.
One lower part of a statue of the seated god Ptah, sawn and repaired.
One sphinx.
One unidentified metal piece.

The favissa contained 38 objects, including (clockwise from top left) a male head made of gilded limestone, the lower part of the limestone statue of the god Ptah, a statuette of Osiris, and a limestone sphinx.
It appeared that the artifacts were buried in a certain order. After digging the pit, also known as a favissa (a cache of sacred objects that are no longer in use), the ancient Egyptians would have put down the lower part of Ptah's limestone statue. The statue was large, and it probably took two to three people to carry it, the researchers said.

Next to the statue, the Egyptians would have placed a wooden effigy of the god Osiris that had metal appliqué, including a beard and two feathers in its crown. Then, the other artifacts would have been distributed around these two artifacts, which were then covered with about 8 inches (20 centimeters) of backfill. This is where the ancient Egyptians placed a statue of a small limestone sphinx.

The pit was then covered with more backfill. At the top, the Egyptians placed a small male head made of gilded limestone, likely for protection, the researchers said.

The objects were made at different times, the researchers found. The statue of Ptah dates to the New Kingdom; the style of the sphinx supports a late Ptolemaic date; and the gilded head dates to the early Ptolemaic period, the researchers said. However, by studying the site's rock layers, the researchers found that the artifacts were buried by the temple's priests during the second half of the Ptolemaic period, between the second century B. and the middle of the first century BC, the researchers wrote in the study.

Read more at Seeker

This Airship Might Provide a Better View of the Big Bang’s Relic Radiation

Airlander 10’s first flight on 2016 August 17
Despite the universe being billions of years old, today we can still see the early stages of the its expansion through a phenomenon called cosmic microwave background radiation. NASA describes the CMB as "literally the remnant heat left over from the Big Bang."

The energy is visible in microwave wavelengths, which means it can't be seen unless you're above the atmosphere somewhere. But observations taken for spacecraft caught something extraordinary: a remarkably uniform background about 2.275 degrees Celsius (36 degrees Fahrenheit) above absolute zero, or the coldest possible temperature allowed by physics. Mapping and understanding the tiny variations of temperature at the part per million level that require ongoing observations and modeling.

Scientists have observed the CMB before with spacecraft, and even a specially adapted 747 called SOFIA (Stratospheric Observatory for Infrared Astronomy). A proposal published in the Monthly Notices of the Royal Astronomical Society suggests using an airship called Airlander 10, which is cheaper than a spacecraft, but allows for lengthy observations of up to weeks at a time.

"The main advantage is flight duration," Stephen Feeney, lead author and a postdoctoral researcher at the Flatiron Institute's Center for Computational Astrophysics in New York City, told Seeker in an email.

"Using remote piloting, Airlander 10 should fly for up to three weeks at a time,” he said. “We could therefore observe the sky roughly 20 times longer on an Airlander 10 flight than using, for example, a 747 like SOFIA. Airlander 10 is also able to operate without an airport, and should have a significantly smaller environmental impact, as it generates 60 percent of its lift through buoyancy."

An image of the cosmic microwave background radiation, including the foreground signal from the Milky Way galaxy (in red). This picture is based on observations from NASA's Wilkinson Microwave Anisotropy Probe, which operated from 2001 to 2010.
Airlander 10 is a hybrid airship — meaning that part of its lift, or ability to fly, comes from being filled with lighter-than-air gas, and the other part of its lift comes from aerodynamics. Originally designed and built for the US Army, the military sold the airship back to the manufacturer in 2016 for civilian use. It is now in test flights, having survived an accident, which damaged the airship, but left the crew unharmed. This means that Feeney's proposal is still in a very early stage.

"We are currently working with Hybrid Air Vehicles, Airlander 10's designers, to ascertain whether the vibrations from Airlander 10's engines are low enough to allow a CMB telescope to gather useful data,” Feeney said. “If this critical criterion is satisfied, we will look to develop the concept further.”

Feeney's research, in part, concerns how to operate CMB detectors at higher altitudes, which requires knowledge of how they perform at sea level, then extrapolating their performance at higher and higher altitudes. The research also seeks to ways to avoid confusing radiation from galaxies, which are closer to us than the CMB. Both galaxies and CMB can emit radiation at the same wavelengths.

"These foregrounds can be cleaned from the CMB by observing the sky at many different wavelengths, as the amplitudes of the foregrounds and CMB change differently with wavelength," Feeney said.

Read more at Seeker

Cosmic Rays Originate Far Beyond the Milky Way

Something out in space has been bombarding Earth with incredibly high energy particles called cosmic rays. The origin of cosmic rays has been a mystery since their discovery over a century ago.

But twelve years of data from an unusual observatory in South America has now confirmed that cosmic rays with the highest energies come from sources outside the Milky Way. In particular, the majority of the high-energy particles originate from an area of the sky that lies almost opposite from the center of our own galaxy, in a region of space with a high concentration of other galaxies. 

“The distribution of arrival directions of the highest energy cosmic ray particles has an enhancement in a broad patch of the sky which is roughly 120 degrees away from a line pointing from Earth to the center of our Milky Way galaxy, meaning cosmic rays coming to the Earth from that patch must be coming from other galaxies,” Gregory Snow, a physics professor from the University of Nebraska-Lincoln, said in an email to Seeker. He is also the education and outreach coordinator for the Pierre Auger Observatory, which is located in western Argentina and was the source of the data.

Snow and a group of more than 400 scientists from 18 countries published last week their analysis of cosmic rays in the journal Science.

He explained the direction of the enhanced patch is consistent with a region of galaxies that is more dense than other regions of the sky.

“This makes sense since we might expect more cosmic ray particles coming from places in the universe where there is a lot of ‘stuff,’” he said.

Scientists collected a dozen years of data on cosmic rays at the Pierre Auger Observatory in Argentina.
Cosmic rays are electrically charged particles, such as protons, that travel near the speed of light. They strike Earth from all directions, and have energies up to one hundred million times higher than those created in man-made accelerators like the Large Hadron Collider. These high-energy cosmic rays — ones with energies reaching quintillions of electron volts — are different from the ones emitted by our sun during flares and coronal mass ejections.

"The sun emits low-energy cosmic ray particles that are detected here on Earth, but they are nowhere near as high energy as the particles detected at the Auger Observatory," Snow explained in a press release.

When the high energy cosmic rays travel across space, the particles can be deflected by magnetic fields, which scramble their paths and sometimes mask their origins.

Detecting cosmic rays is even more challenging because the highest energy particles — the ones that are most mysterious and rare — reach Earth at a rate of only one particle per square kilometer each year.

That’s where the Pierre Auger Observatory comes in. The observatory uses 1,660 tanks filled with ultra-pure water, spread over a 1,800-square-mile (3,000-square-kilometer) grid in Argentina. Each 3,000-gallon (12,000 liter) tank is separated from the other tanks by about a mile (1.5 km) and are enclosed to make them completely dark inside. When cosmic ray particles pass through the water, their electromagnetic shock waves produce radiation called Cherenkov light that can be measured by special instruments mounted in the tanks.

There are also separate, independent detectors called air fluorescence telescopes that track the development of what is called “air showers.” Cosmic rays interacting with Earth’s atmosphere produce a cascade effect, creating extensive showers that contain billions of secondary particles. The air fluorescence telescopes observe ultraviolet light emitted high in Earth's atmosphere from the showers.  These air showers can also cause nearly simultaneous bursts of light in more than five tanks.

Using the two detectors, scientists can determine the energy of the primary cosmic ray particles based on the amount of light they detect from a sample of secondary particles. Additionally, slight differences in the detection times at different tank positions help scientists determine the trajectory of the incoming cosmic rays.

In over a dozen years of operation, the Auger Observatory has collected some of the highest quality information about the types of particles in primary cosmic rays. Comparing results from the different types of detectors also helps scientists reconcile the two sets of data and produce the most accurate results about the energy of primary cosmic rays.

University of Nebraska-Lincoln physics professor Gregory Snow stands near one of the cosmic ray particle detectors used by the Pierre Auger Observatory in Argentina.
But why study these high-energy cosmic rays?

For one thing, scientists like a good mystery and the origins of cosmic rays is one of the biggest unknowns in physics.

But understanding them better could lead to improved insights on fundamental physics, such as how our universe was created, and why objects have mass. Snow told Seeker high-energy cosmic rays are clues to the very structure of the universe.

“High-energy cosmic ray particles are one of several messengers from outer space that we use to learn about the structure of the universe, for example, the distribution of where the billions of other galaxies apart from the Milky Way are located,” he said. “We now know that galaxies are not uniformly distributed in outer space. Rather they group themselves in clusters and super-clusters.”

Also, scientists don’t know the exact source of high-energy cosmic rays. There have been theories, but the intense conditions needed to generate such energetic particles can be mind-boggling.

“We know that shock waves coming from stars dying in the form of a supernova could accelerate cosmic ray particles up to energies reaching about 10 to the 15th electron volts,” Snow explained. “But our paper is about cosmic ray particles of much higher energies, greater than 8 times 10 to the 18th electron volts. We can only speculate what the sources of these particles may be.”

Snow said physicists can learn the most about specific sources by studying the arrival directions of the very highest energy particles, since their measured arrival directions essentially point straight back to their sources.

Read more at Seeker

Sep 24, 2017

World's first 'molecular robot' capable of building molecules

Molecular robotics represents the ultimate in the miniaturization of machinery, researchers say.
Scientists at The University of Manchester have created the world's first 'molecular robot' that is capable of performing basic tasks including building other molecules.

The tiny robots, which are a millionth of a millimetre in size, can be programmed to move and build molecular cargo, using a tiny robotic arm.

Each individual robot is capable of manipulating a single molecule and is made up of just 150 carbon, hydrogen, oxygen and nitrogen atoms. To put that size into context, a billion billion of these robots piled on top of each other would still only be the same size as a single grain of salt.

The robots operate by carrying out chemical reactions in special solutions which can then be controlled and programmed by scientists to perform the basic tasks.

In the future such robots could be used for medical purposes, advanced manufacturing processes and even building molecular factories and assembly lines. The research will be published in Nature on Thursday 21st September.

Professor David Leigh, who led the research at University's School of Chemistry, explains: 'All matter is made up of atoms and these are the basic building blocks that form molecules. Our robot is literally a molecular robot constructed of atoms just like you can build a very simple robot out of Lego bricks. The robot then responds to a series of simple commands that are programmed with chemical inputs by a scientist.

'It is similar to the way robots are used on a car assembly line. Those robots pick up a panel and position it so that it can be riveted in the correct way to build the bodywork of a car. So, just like the robot in the factory, our molecular version can be programmed to position and rivet components in different ways to build different products, just on a much smaller scale at a molecular level.'

The benefit of having machinery that is so small is it massively reduces demand for materials, can accelerate and improve drug discovery, dramatically reduce power requirements and rapidly increase the miniaturisation of other products. Therefore, the potential applications for molecular robots are extremely varied and exciting.

Prof Leigh says: 'Molecular robotics represents the ultimate in the miniaturisation of machinery. Our aim is to design and make the smallest machines possible. This is just the start but we anticipate that within 10 to 20 years molecular robots will begin to be used to build molecules and materials on assembly lines in molecular factories.'

Whilst building and operating such tiny machine is extremely complex, the techniques used by the team are based on simple chemical processes.

Prof Leigh added: 'The robots are assembled and operated using chemistry. This is the science of how atoms and molecules react with each other and how larger molecules are constructed from smaller ones.

Read more at Science Daily

Scientists sequence asexual tiny worm whose lineage stretches back 18 million years

Pictured is Diploscapter pachys (D. pachys), a newly sequenced roundworm that is approximately one-third of a millimeter long and one of a very few known animals that have only a single chromosome.
A team of scientists has sequenced, for the first time, a tiny worm that belongs to a group of exclusively asexual species that originated approximately 18 million years ago -- making it one of the oldest living lineages of asexual animals known. The work reveals how it has escaped the evolutionary dead end usually met by organisms that do not engage in sex.

"Scientists have been trying to understand how some animals can survive for millions of years without sex because such strict, long-term abstinence is very rare in the animal world," explains New York University Biology Professor David Fitch, one of the co-authors of the research. "This phenomenon is a significant one in understanding evolutionary genetics because it runs counter to the widely accepted view that sexual reproduction is required to eliminate deleterious mutations and for adaptation to a changing environment."

"For example, in the short term, inheriting copies of both parents' genes usually provides good insurance against mutations that might kill the function of one of those gene copies -- a process called complementation," Fitch continues. "In the long term, producing offspring via intercourse allows for adaptation to changing conditions over time because it produces variation through genetic shuffling, or recombination. However, because such shuffling does not occur within asexual species, they tend to go extinct rapidly. So, it has been a longstanding mystery in biology how some asexual animals have survived for so many generations."

The research, conducted by researchers in NYU's Center for Genomics and Systems Biology and Duke University's Center for Genomic and Computational Biology, appears in the journal Current Biology.

The newly sequenced worm, Diploscapter pachys, is a tiny, transparent, free-living roundworm and closely related to Caenorhabditis elegans, an organism commonly used for biomedical research.

Unlike C. elegans, however, D. pachys is asexual.

In making this determination, the scientists used DNA to derive a genealogy that revealed D. pachys belongs to a group of exclusively asexual species that originated approximately 18 million years ago.

In a closer examination of how D. pachys reproduces, the research team found that, like many other asexual organisms, the process of making germ cells -- sperm or ova -- had been modified to prevent recombination, or the reshuffling that results from sexual reproduction.

"Basically, the animals were cloning themselves," explains Fitch. In addition, when the researchers studied its chromosomes, they found something even more surprising: there was only one pair of chromosomes.

Close relatives, such as C. elegans, have 5-7 chromosomes, but a single-chromosome pair, the scientists say, is so rare in higher organisms that only two other animal species are known with this condition: an ant and a parasitic roundworm.

The researchers decided to sequence the genome of D. pachys to test how the single chromosome was structured, whether by loss or by fusion of multiple ancestral chromosomes.

Their results showed that D. pachys fuses the six chromosomes of its ancestor into a single chromosome and skips the first division of meiosis, where genes are recombined, so that its offspring keeps the high genetic diversity of the parents.

Read more at Science Daily

Sep 22, 2017

Why poison frogs don't poison themselves

The phantasmal poison frog, Epipedobates anthonyi, is the original source of epibatidine, discovered by John Daly in 1974. In fact, epibatidine is named for frogs of this genus. Epibatidine has not been found in any animal outside of Ecuador, and its ultimate source, proposed to be an arthropod, remains unknown. This frog was captured at a banana plantation in the Azuay province in southern Ecuador in August 2017.
Don't let their appearance fool you: Thimble-sized, dappled in cheerful colors and squishy, poison frogs in fact harbor some of the most potent neurotoxins we know. With a new paper published in the journal Science, scientists are a step closer to resolving a related head-scratcher -- how do these frogs keep from poisoning themselves? And the answer has potential consequences for the fight against pain and addiction.

The new research, led by scientists at The University of Texas at Austin, answers this question for a subgroup of poison frogs that use the toxin epibatidine. To keep predators from eating them, the frogs use the toxin, which binds to receptors in an animal's nervous system and can cause hypertension, seizures, and even death. The researchers discovered that a small genetic mutation in the frogs -- a change in just three of the 2,500 amino acids that make up the receptor -- prevents the toxin from acting on the frogs' own receptors, making them resistant to its lethal effects. Not only that, but precisely the same change appeared independently three times in the evolution of these frogs.

"Being toxic can be good for your survival -- it gives you an edge over predators," said Rebecca Tarvin, a postdoctoral researcher at UT Austin and a co-first author on the paper. "So why aren't more animals toxic? Our work is showing that a big constraint is whether organisms can evolve resistance to their own toxins. We found evolution has hit upon this same exact change in three different groups of frogs, and that, to me, is quite beautiful."

There are hundreds of species of poisonous frogs, each of which uses dozens of different neurotoxins. Tarvin is part of a team of researchers, including professors David Cannatella and Harold Zakon in the Department of Integrative Biology, who have been studying how these frogs evolved toxic resistance.

For decades, medical researchers have known that this toxin, epibatidine, also can act as a powerful nonaddictive painkiller. They've developed hundreds of compounds from the frogs' toxin, including one that advanced in the drug-development process to human trials before being ruled out due to other side effects.

The new research -- showing how certain poison frogs evolved to block the toxin while retaining use of receptors the brain needs -- gives scientists information about epibatidine that could eventually prove helpful in designing drugs such as new pain relievers or drugs to fight nicotine addiction.

"Every bit of information we can gather on how these receptors are interacting with the drugs gets us a step closer to designing better drugs," said Cecilia Borghese, another co-first author of the paper and a research associate in the university's Waggoner Center for Alcohol and Addiction Research.

Changing the Lock

A receptor is a type of protein on the outside of cells that transmits signals between the outside and the inside. Receptors are like locks that stay shut until they encounter the correct key. When a molecule with just the right shape comes along, the receptor gets activated and sends a signal.

The receptor that Tarvin and her colleagues studied sends signals in processes like learning and memory, but usually only when a compound that is the healthy "key" comes into contact with it. Unfortunately for the frogs' predators, toxic epibatidine also works, like a powerful skeleton key, on the receptor, hijacking cells and triggering a dangerous burst of activity.

The researchers found that poison frogs that use epibatidine have developed a small genetic mutation that prevents the toxin from binding to their receptors. In a sense, they've blocked the skeleton key. They also have managed, through evolution, to retain a way for the real key to continue to work, thanks to a second genetic mutation. In the frogs, the lock became more selective.

Fighting Disease

The way that the lock changed suggests possible new ways to develop drugs to fight human disease.

The researchers found that the changes that give the frogs resistance to the toxin without changing healthy functioning occur in parts of the receptor that are close to, but don't even touch epibatidine. Borghese and Wiebke Sachs, a visiting student, studied the function of human and frog receptors in the lab of Adron Harris, another author on the paper and associate director of the Waggoner Center.

"The most exciting thing is how these amino acids that are not even in direct contact with the drug can modify the function of the receptor in such a precise way," Borghese said. The healthy compound, she continued, "keeps working as usual, no problem at all, and now the receptor is resistant to epibatidine. That for me was fascinating."

Understanding how those very small changes affect the behavior of the receptor might be exploited by scientists trying to design drugs that act on it. Because the same receptor in humans is also involved in pain and nicotine addiction, this study might suggest ways to develop new medications to block pain or help smokers break the habit.

Retracing Evolution

Working with partners in Ecuador, the researchers collected tissue samples from 28 species of frogs -- including those that use epibatidine, those that use other toxins and those that are not toxic. Tarvin and hear colleagues Juan C. Santos from St. John's University and Lauren O'Connell from Stanford University sequenced the gene that encodes the particular receptor in each species. She then compared subtle differences to build an evolutionary tree representing how the gene evolved.

This represents the second time that Cannatella, Zakon, Tarvin and Santos have played a role in discovering mechanisms that prevent frogs from poisoning themselves. In January 2016, the team identified a set of genetic mutations that they suggested might protect another subgroup of poison frogs from a different neurotoxin, batrachotoxin. Research published this month was built on their finding and conducted by researchers from the State University of New York at Albany, confirming that one of UT Austin's proposed mutations protects that set of poison frogs from the toxin.

Read more at Science Daily

Solving the Easter Island population puzzle

A detailed study of Easter Island's farming potential reveals the population may have reached 17,500 people in its heyday, which could help unravel the mystery of its giant statues.
Easter Island, known as Rapa Nui by its inhabitants, has been surrounded in mystery ever since the Europeans first landed in 1722. Early visitors estimated a population of just 1,500-3,000, which seemed at odds with the nearly nine hundred giant statues dotted around the Island. How did this small community construct, transport and erect these large rock figures?

A new study, published in the open-access journal Frontiers in Ecology and Evolution, hopes to unravel this mystery by giving the best estimate yet of the maximum population size sustained by Easter Island in its heyday.

"Despite its almost complete isolation, the inhabitants of Easter Island created a complicated social structure and these amazing works of art before a dramatic change occurred," says Dr. Cedric Puleston, lead author of this study, based at the Department of Anthropology, University of California, Davis, USA. "We've tried to solve one piece of the puzzle -- to figure out the maximum population size before it fell. It appears the island could have supported 17,500 people at its peak, which represents the upper end of the range of previous estimates."

He adds, "If the population fell from 17,500 to the small number that missionaries counted many years after European contact, it presents a very different picture from the maximum population of 3,000 or less that some have suggested."

Previous archaeological evidence implies the indigenous people numbered far greater than the 1,500-3,000 individuals encountered in the 18th century. The population history of the island remains highly controversial. In addition to internal conflict, the population crash has been attributed to "ecocide," in which the Island's resources were exhausted by its inhabitants, reducing its ability to support human life.

Puleston and his colleagues examined the agricultural potential of the Island before these events occurred, to calculate how many people the Island could sustain.

"The project, funded by the U.S. National Science Foundation, involved a number of really good researchers, including archaeologists, a local expert in Rapa Nui culture, a soil scientist, a biogeochemist, and a population biologist, to get a thorough picture of what the island was like before European contact," he explains.

"We examined detailed maps, took soil samples around the Island, placed weather stations, used population models and estimated sweet potato production. When we had doubts about one of these factors we looked at the range of its potential values to work out different scenarios."

They found 19% of the Island could have been used to grow sweet potatoes, which was the main food crop. By using information on how birth and death rates at various ages depend on food availability, the researchers calculated the population size that level of production could sustain.

"The result is a wide range of possible maximum population sizes, but to get the smallest values you have to assume the worst of everything," says Puleston. "If we compare our agriculture estimates with other Polynesian Islands, a population of 17,500 people on this size of island is entirely reasonable."

Read more at Science Daily

Children Internalize Gender Stereotypes as Early as Age Ten

Girls are vulnerable and boys are stronger. Boys should have the courage to ask a girl out. If a boy gets his nails done, there’s definitely something feminine about him. Girls should prepare to become wives and mothers, and boys should focus on their careers.

In countries across the world, regardless of economic status, gender stereotypes are thriving. For sure, cultural variations exist, but a new global study of adolescents published in the US-based Journal of Adolescent Health suggests stereotypes begin seeping into the mindset of children early — as early as age 10.

Internalizing unequal gender norms has both immediate and long-term consequences on sexual, reproductive, and mental health, including risk of HIV and other sexually transmitted diseases, complications associated with early pregnancy, substance and alcohol abuse, depression, and suicide. These health concerns, according to the study, begin during adolescence and can carry over into adulthood.

“We found children at a very early age — from the most conservative to the most liberal societies — quickly internalize this myth that girls are vulnerable and boys are strong and independent,” Robert Blum of Johns Hopkins University and director of the Global Early Adolescent Study said in a press release accompanying publication of the study.

The research was a collaboration between the Johns Hopkins Bloomberg School of Public Health and the World Health Organization.

Researchers across 15 countries, including the United States, China, Kenya, Belgium, Nigeria, India, South Africa, and Scotland, among others, interviewed over 400 children aged 10 to 14, along with their parents.

Perception of distinct, gendered roles takes root in a child’s mindset between the age of 10 and 14, according to the report. And while the impact of these stereotypes is not surprising, “the fact that they are so common across cultures and economic status and ingrained in children at such a relatively young age, is unexpected,” Kristin Mmari, a professor at Johns Hopkins University and lead researcher on study, told Seeker.

A 12-year-old girl participating in the study from Delhi recalled one of her female classmates being scolded by a teacher for wearing short skirts and playing with boys. “After the school got over, she was sitting alone when a boy went inside the school and raped her as she wearing short skirt,” the girl is quoted as saying in the study.

The report also highlights progress in challenging gender norms.

In Belgium, girls’ participation in sports was celebrated. “Girls are [one] hundred percent [as involved as] boys in football,” a 13-year-old boy is quoted saying. “[Today] there are more girls playing football than boys.”

In China, however, an 11-year-old boy said girls must display certain male traits like strength, fearlessness, and indifference to pain, before successfully participating in the sport.

A message of strength and virility being passed onto boys across cultures is equally threatening to their development, the study suggests. In China, India, Belgium, and the United States, researchers saw that girls are pushing the boundaries of gender norms more than boys. But boys exploring stereotypically female behavior were seen as socially inferior. As a result, they suffer and tend to be more self-harming, said the researchers.

Mmari says stereotypes can be deconstructed and reformed and are amenable to change. “But do I think it will happen quickly? No,” she said.

Read more at Seeker

Porpoise Burial by Medieval Monks Creates Puzzling Grave Mystery

A porpoise from the medieval period was found buried in what appears to be a formal grave on the island of Chapelle dom Hue in the English Channel.
Folklore holds that the little island of Chapelle Dom Hue, in the English Channel west of Guernsey, was the location of a scenic retreat for medieval monks from the Benedictine priory of Lihou, which is a slightly larger island just to the south. Guernsey archaeologist Philip de Jersey and his colleagues are currently excavating the site to determine, in part, what the monks might have left there.

Recently, de Jersey and his team spotted the outline of a feature in the soil that looked like a grave.

“It certainly resembled medieval graves we have excavated in several sites on the island, and it was only a little way off the east-west orientation, as one would usually expect,” de Jersey told Seeker from the site.

A few days later, he and his team started to excavate the feature and uncovered a skull, which he initially thought was the top of a human skull. While dirt was removed, however, the skull grew ever larger in appearance.

As it turns out, the skull and other remains belonged, not to a human, but to a porpoise. The discovery is the world’s only known porpoise burial from the medieval era or earlier.

The archaeologists were astonished.

“It was entirely consistent with a human burial, which is one of the most puzzling aspects,” de Jersey said. “The grave cut has been dug very carefully, with vertical sides and a flat base cut into the underlying bedrock. This has taken some considerable care and effort.”

The buried porpoise as it was first being uncovered.
Like the beginning of a great murder mystery — the porpoise does appear to have been killed — there is a collection of clues and other information, some of which may have nothing to do with the burial.

So far, de Jersey and his team on the island have uncovered the ruins of a building there erected on an east-west alignment, which supports a religious function, according to the researchers.

“It was quite a substantial structure, small in size, but with thick walls,” de Jersey said.

He added that they have also found a lot of old pottery known as Normandy gritty ware, which was imported to the Channel Islands between the late 10th and early-15th centuries. A priory on Lihou was in use from the mid 12th to the early 14th or early-15th century, but the Chapelle Dom Hue pottery suggests that this smaller island was only occupied by the monks for a relatively short time, probably in the later-14th century.

A photo taken from west of the site, with the medieval building at Chapelle Dom Hue visible in the foreground
Evidence for an even earlier occupation of Chapelle Dom Hue was also found, with flint tools going back to the Neolithic Period (15,200 BC–2,000 BC). The porpoise burial, though, is at the medieval level of the site.

The researchers suspect that the animal was butchered before it was put into the ground.

“The bone preservation, apart from the skull, is very poor in our acidic soul, but it appears as though there are various articulated portions in the grave, not in the association one would expect if it was a complete body,” de Jersey explained.

The monks may therefore have viewed the porpoise more as food than as a revered, sentient being.

“One possibility we have considered is that the ‘grave’ is not a grave at all, but a pit carefully cut in which the butchered porpoise was buried in salt, in order to preserve portions of it,” de Jersey said. “There is contemporary literary evidence of porpoises, or parts of porpoise, being around for longer than it would have been fresh, therefore it must have been preserved somehow, whether through drying or salting.”

Researchers excavating at Chapelle Dom Hue, with Guernsey in the distance
Salting of fish and other edible marine life at the time was normally done in barrels, though. The researchers wonder if the large size of the porpoise might have necessitated a different approach for preparing it.

“If that’s true, then obviously it was never recovered, for some reason — or perhaps it just didn’t work as a technique, so they left it in the ground,” de Jersey said.

Medieval cookbooks do include dishes with porpoise as an ingredient. The late-14th century chef’s tome Forme of Cury, for example, contains such a recipe.

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