Jul 26, 2017

Traces of adaptation and cultural diversification found among early North American stone tools

Scientists analyzed three-dimensional models of Clovis projectile points from Smithsonian and other museum collections to examine how patterns and marks made in crafting these tools began to vary regionally 12,500 years ago. These regional differences signal cultural diversification and adaptation, suggesting that groups of early hunter-gatherer Americans may have changed the way they were social interacting at this time. This figure shows one analysis used to study shapes left behind from their production on either side of the projectile points.
Using new methods to analyze stone projectile points crafted by North America's earliest human inhabitants, Smithsonian scientists have found that these tools show evidence of a shift toward more experimentation in their production beginning about 12,500 years ago, following hundreds of years of consistent stone-tool production created using uniform techniques. The findings provide clues into changes in social interactions during a time when people are thought to have been spreading into new parts of North America and adapting to different environments, beginning a period of cultural diversification.

The research team, led by Sabrina Sholts, a curator in the Department of Anthropology at the Smithsonian's National Museum of Natural History, and Sebastian Wärmländer at Stockholm University, used digital 3-D models to scrutinize the angles and contours on the surfaces of North American projectile points. In doing so, they discovered a turning point at which the techniques used to produce the points became more variable. That variability suggests that individual toolmakers, who may have had fewer opportunities than their predecessors to learn from others, began working out how to make the tools on their own. The findings were reported July 12 in the journal PLOS ONE.

"Our study really allows stone tools to speak in a new way," said Joseph Gingerich, a research associate at the museum and assistant professor of anthropology at Ohio University. "By being able to document subtle changes in stone tool technology, we can better understand how social interactions among artisans changed in North America over 12,000 years ago."

The earliest well-documented group of people in North America, known as Clovis, is recognized by distinctive pointed stone projectiles that appear about 13,500 years ago. These culture-defining tools, called Clovis points, are sharp-edged and symmetrical, with a groove near the base -- called a flute -- where a spear shaft may have fit. Anthropologists consider them to be a very sophisticated technology.

The highly mobile hunter-gatherers of the Clovis culture spread quickly across North America, and Clovis points have been found all over the continent. In 2012, Sholts and colleagues analyzed 50 authentic and replicate Clovis points, examining how their surfaces had been shaped as flakes of stone were chipped away to craft the tool. Using an approach Sholts and Wärmländer originally developed for studying bones, the researchers laser scanned each point to create a three-dimensional model and then analyzed its contours, measuring and comparing subtle surface features that cannot be discerned by eye. "It's a way to capture all the individual actions to reduce the core, which reflect the technique used to shape it," Sholts said.

The analysis revealed remarkable consistency among the ancient artifacts compared to almost perfect copies made by a modern knapper, an artisan that crafts stone tools using ancient techniques. The team concluded that the manufacturing technique used by the Clovis people was so uniform that it must have been passed on directly from one knapper to another.

According to the archaeological record, Clovis technology was used for several hundred years. A variety of other styles emerged later, though they never spread across the continent like Clovis points did. To learn more about the groups that manufactured these later styles, the authors of the new study analyzed the surface features of 100 projectile points from collections at several museums, including the Smithsonian collection, which is curated by anthropologist Dennis Stanford.

The new study included Clovis points and samples of four later styles of fluted points, which had been recovered from sites in the eastern United States. The team analyzed the points' surface contours as they had done in the earlier study and also introduced a new method of analyzing digital models to assess the objects' three-dimensional asymmetry.

Using another new technique developed by Wärmländer and co-author Stefan Schlager of the University of Freiburg, the team determined that the overall three-dimensional shapes of the points did not vary significantly. However, they did find increased variability in the surface contours among some of the later styles of points, indicating that those tools had not been produced using a consistent technique.

The increase in variability among the later points suggests a decrease in social learning and possibly a reduction in overall interactions among North American populations beginning around 12,500 years ago, the researchers say. This is consistent with anthropologists' current thinking about how people were living during this time. "There seems to be evidence of increased experimentation during this period, due to groups moving away from each other and pushing into new environments," Sholts said.

Read more at Science Daily

New bird that humans drove to extinction discovered in Azores

Reconstruction of Pyrrhula crassa (left) and skull (right).
Inside the crater of a volcano on Graciosa Island in the Azores archipelago, in the Atlantic Ocean, an international team of researchers has discovered the bones of a new extinct species of songbird, a bullfinch which they have named Pyrrhula crassa. The remains were found in a small cavity through which time ago the lava flowed. This bird disappeared a few hundreds of years ago due to human colonization of the islands and the introduction of invasive species.

Until hundreds of years ago, a species of bullfinch, a small songbird with a very short and robust beak, lived on Graciosa Island in the Azores archipelago. The arrival of humans to this island, however, depleted its population and it ended up going extinct, as was the case with numerous bird species on other islands, such as the Canaries and Madeira.

Now, an international team of scientists, backed by a project led by Josep Antoni Alcover, from the Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB), has discovered the bones of this bullfinch, called Pyrrhula crassa, in a cave located in a 12,000-year-old volcano in the southeast of the island.

"It is the first extinct passerine bird described in the archipelago, and it won't be the last," states Alcover, co-author of the study published in Zootaxa which focused on the analysis of beak morphology in order to determine the new species.

Despite there being few known remains of this bird, they are sufficiently distinctive for the scientists to have succeeded in establishing that they belong to a new extinct species of bullfinch.

The new bird, being the largest of its genus according to the size of the skull remains found, recalls due to its flying ability the existing bullfinch from the other Azores island (São Miguel) which is 'vulnerable' to extinction because of the expansion of agriculture and the disappearance of laurel forests.

"Its short and wide beak was not just considerably bigger, but also relatively higher than that of the common bullfinch or that from São Miguel, with a very robust configuration reminiscent to an extent of the beak of a small parrot," asserts the researcher.

Invasions wiped out the birds

These islands were colonized during the 13th century by the Portuguese, although they could have been visited by Vikings over one thousand years ago. Just as has happened on many other islands, such as the Canaries or Madeira, different bird species have disappeared throughout the last millennium due to the arrival of humans along with various invasive species.

Human colonization led to the destruction and burning of the islands' habitats in which humans started settling, and they impacted on the birds which were part of the indigenous fauna. P. crassa was no exception, finding itself affected until its extinction.

Read more at Science Daily

Dawn of the cosmos: Seeing galaxies that appeared soon after the Big Bang

Milestones in the history of the Universe (not to scale). The intergalactic gas was in a neutral state from about 300,000 years after the Big Bang until light from the first generation of stars and galaxies began to ionize it. The gas was completely ionized after 1 billion years. The LAGER study takes a close look at the state of the Universe at 800 million years (yellow box) to investigate when and how this transformation occurred.
Arizona State University astronomers Sangeeta Malhotra and James Rhoads, working with international teams in Chile and China, have discovered 23 young galaxies, seen as they were 800 million years after the Big Bang. The results from this sample have been recently published in the Astrophysical Journal.

Long ago, about 300,000 years after the beginning of the universe (the Big Bang), the universe was dark. There were no stars or galaxies, and the universe was filled with neutral hydrogen gas. In the next half billion years or so the first galaxies and stars appeared. Their energetic radiation ionized their surroundings, illuminating and transforming the universe.

This dramatic transformation, known as re-ionization, occurred sometime in the interval between 300 million years and one billion years after the Big Bang. Astronomers are trying to pinpoint this milestone more precisely and the galaxies found in this study help in this determination.

"Before re-ionization, these galaxies were very hard to see, because their light is scattered by gas between galaxies, like a car's headlights in fog," says Malhotra. "As enough galaxies turn on and 'burn off the fog' they become easier to see. By doing so, they help provide a diagnostic to see how much of the 'fog' remains at any time in the early universe."

The Dark Energy Camera

To detect these galaxies, Malhotra and Rhoads have been using the Dark Energy Camera (DECam), one of the new powerful instruments in the astronomy field. DECam is installed at the National Optical Astronomy Observatory (NOAO)'s 4-meter Blanco Telescope, located at the Cerro Tololo Inter-American Observatory (CTIO), in northern Chile, at an altitude of 7,200 feet.

"Several years ago, we carried out a similar study using a 64-megapixel camera that covers the same amount of sky as the full moon," says Rhoads. "DECam, by comparison, is a 570-megapixel camera and covers 15 times the area of the full moon in a single image."

DECam was recently made even more powerful when it was equipped with a special narrowband filter, designed at ASU's School of Earth and Space Exploration (SESE), primarily by Rhoads and Zheng (who was a SESE postdoctoral fellow and is currently at the Shanghai Astronomical Observatory in China), with assistance from Alistair Walker of NOAO.

"We spent several months refining the design of the filter profile, optimizing the design to get maximum sensitivity in our search" says Zheng, the lead author of this study.

Touching the Cosmic Dawn

The galaxy search using the ASU-designed filter and DECam is part of the ongoing "Lyman Alpha Galaxies in the Epoch of Reionization" project (LAGER). It is the largest uniformly selected sample that goes far enough back in the history of the universe to reach cosmic dawn.

"The combination of large survey size and sensitivity of this survey enables us to study galaxies that are common but faint, as well as those that are bright but rare, at this early stage in the universe," says Malhotra.

Junxian Wang, a co-author on this study and the lead of the Chinese LAGER team, adds that "our findings in this survey imply that a large fraction of the first galaxies that ionized and illuminated the universe formed early, less than 800 million years after the Big Bang."

Read more at Science Daily

A Universal ‘Language’ of Arousal Connects Humans and the Animal Kingdom

Orpheus Charming the Animals by Jacob Hoefnagel (1613)
Over a century ago, naturalist Charles Darwin observed that all humans, as well as other animals, exhibit and express emotion in remarkably similar ways. He theorized that vocal expressions of feelings date back to the earliest terrestrial species, hinting that all land animals — and birds too — share a basic, inherent understanding of each other.

New research not only supports Darwin’s views, but also identifies a universal “language” of arousal emitted and understood by amphibians, reptiles, birds, and mammals. The findings, published in the journal Proceedings of the Royal Society B, suggest that we are at least somewhat like the famous fictional character Doctor Dolittle, who could decipher animal communications with ease.

“Our study shows that humans are naturally able to recognize emotional arousal across all classes of vocalizing animals,” said lead author Piera Filippi, a postdoctoral researcher at the University of Aix-Marseille and the Max Planck Institute for Psycholinguistics. “This outcome may find an important application in animal welfare, suggesting that humans may rely on their intuition to assess when animals are stressed.”

Prior research additionally suggests that animals understand human emotional vocal expressions. Pet owners are often more attuned to this, given the reactions that dogs, cats, horses, birds, rodents, and more have to a range of owner outbursts, from angry scolding to happy praise.

For the latest study, Filippi, senior author Onur Gunturkun, and their team went beyond investigating such a familiar collection of animal pets. They instead gathered 180 recordings of vocalizations from nine different and very diverse species: hourglass treefrog, black-capped chickadee, common raven, American alligator, African bush elephant, giant panda, domestic pig, and Barbary macaque. People who spoke English, Mandarin, and German were then recruited to evaluate the levels of arousal communicated in each animal recording.

The human listeners, no matter their native language, aced the tests. This indicates that human ability to assess vocal expressions of arousal — whether emitted due to sexual bliss, infant distress, or terror over a predator — is biologically rooted and somehow cemented in our DNA.

The scientists further conducted an acoustic analysis of the recordings. Pairing this data with the findings concerning the human listeners, the researchers discovered that people use multiple acoustic parameters to infer levels of arousal in vocalizations. Mainly, however, humans rely on fundamental frequency cues and the forcefulness of the sounds.  

The primary explanation for the ability, seemingly shared across much of the animal kingdom, has to do with the body-sound connection.

“Across vocalizing animals, higher levels of emotional intensity may induce the contraction of muscles that are required for vocal production,” Filippi explained. “This modification alters the quality of the sounds produced, often resulting in changes related to the perceived frequency of the sound.”

Whether the vocalizer is a pissed off pig or a playful elephant, the resulting sounds will then be directly affected by muscle contractions that, in turn, are impacted by the animal’s emotions at the time.

The researchers believe their study’s findings could extend to marine species with audible forms of communication. We therefore should be able to identify a dolphin’s levels of arousal, for example, just by hearing its vocalizations, and vice versa.

It may be that skills for vocal expression in marine and terrestrial species evolved from a common ancestor. This underlying connection, as well as the shared basic universal “language,” are tied to critical life-and-death concerns.

“The ability to recognize emotional content across diverse species may have favored the perception of heightened levels of threat or danger in the surrounding environment,” Filippi said. “This may have increased survival opportunities.”

Infant distress calls appear to be the most easily understood, from baby alligators calling for their mothers to young giant pandas squeaking, growling, barking, and huffing. The researchers suspect that this primal ability to decipher baby speak is “particularly salient to caregivers.”

Some animals can even manipulate humans via their infant-resembling cries. Earlier research, for example, found that cats can purr in the same frequency range of a crying baby when soliciting food from their owners.

It remains unclear if insects share the ability of other animals in deciphering the arousal levels of various species’ communications. Filippi explained that insects produce sounds that differ in the level of emotional intensity through stridulation, which refers to vibration resulting from rubbing two body structures against each other. Since the sound-production mechanism is different from that of most other animals, insects may not be included in the universal “language” that connects other creatures.

Another identified disconnect exists between how humans mentally process speech versus nonverbal emotional communications like screams of pain, pleasure, and fear. “Spoken language can be highly emotional,” Filippi said. “However, the fine-tuned articulatory movements involved in speech production may constrain the perception of emotional intensity encoded in the signal.”

Read more at Seeker

The Sperm Counts of Western Men Have Declined Dramatically, Alarming Experts

In 1992, scientists from Denmark published a study claiming that there had been a decline in the quality of men’s semen over the preceding 50 years. Though worries have persisted since then, it has been hard to back up this claim. Now a comprehensive new study has emerged that appears to support the research from decades ago.

The latest study was a meta-analysis of English-language studies on sperm count and concentration that was published this week in the journal Human Reproduction Update. Led by researchers from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine and the Icahn School of Medicine at Mount Sinai, the work analyzed 185 studies on sperm count and quality that were published between 1973 and 2011.

The findings, the researchers say, are unnerving.

After combing through the material, the researchers found a large decrease in sperm quality among men from North America, Europe, Australia, and New Zealand. The drop was particularly notable among men who had never had kids and were unaware of their fertility status. In these men, they found a 52.5 percent drop in sperm concentration, and a 59.3 percent decrease in total sperm count.

They did not find the same decrease in men from non-Western countries, although the authors acknowledged that this could potentially be due to a lack of data.

The authors of the study also pointed out the fact that the decline doesn’t seem to be leveling off. “This study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count,” said lead author Dr. Hagai Levine, an epidemiologist from the Hebrew University of Jerusalem's faculty of medicine, in a statement.

Birth and fertility rates in the United States have continually gone down since around 2007. According to data from the World Bank, the current US birth rate is about 12.4 babies per population of 1,000 people, down from 14.8 in 1973 (the year that researchers began looking at the data).

In addition, low sperm count has more consequences than fertility and childbirth. The researchers pointed out in their meta-analysis that “poor sperm count is associated with overall morbidity and mortality.” In other words, men who have low sperm count tend to have other health problems as well.

It is important to note that there is so far no conclusive evidence about why the sperm count has dropped. The authors speculate it is due to environmental and lifestyle causes, including pesticides, smoking, and obesity. Their assessment didn’t establish any causal links, however.

“If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future," Levine told the BBC, warning ominously that “it may be the extinction of the human species.”

Read more at Seeker

Jul 25, 2017

Detecting Alien Life Will Likely Be a Protracted Process, Not a Eureka Moment

Would it be easy to determine if the source of a mysterious radio signal was aliens? Probably not. A new paper argues that contact with extraterrestrials will likely be discovered through a prolonged, incremental process rather than an instantaneous eureka-like moment. Eureka — what the ancient Greek mathematician Archimedes allegedly said when he cracked a tough science problem about water displacement — tends to be the exception in science rather than the rule.

Attributing scientific progress to eureka moments is popular because it is easy to understand, argues Milan Cirkovic, a senior research associate at the Astronomical Observatory of Belgrade and an assistant physics professor at the University of Novi Sad in Serbia and Montenegro. But, he writes in the journal Space Policy, "It puts too big an emphasis on the 'origin myths' and the role of great personalities, key moments, events, and circumstances in any historical process.”

Cirkovic said in an email that the community involved in the search for extraterrestrial intelligence (SETI) should instead be prepared for a process that would take a very long time. It may take decades as the SETI community looks at all the reasons aliens might not be the source of a mysterious signal.

"I have only tried to point out that both history of science and logic and common sense suggest — on a descriptive level — that contact will be a protracted affair, probably not recognizable as such over timescales of years or decades," Cirkovic said. He was careful not to say how contact might proceed, but that it would take a long time and repeated observations.

Think about the protracted debate concerning "Tabby's star," which is showing strange brightening and dimming. Some say it's due to a possible "alien megastructure," while others are pointing to various natural processes, such as exocomets.

"More structure is obviously necessary, as far as signals are concerned," Cirkovic said. "The example often quoted (first due to Nikola Tesla, who was somewhat forgotten as a SETI pioneer) is the presence of prime numbers 2, 3, 5, 7, 11, ... etc. in the signal."

Prime numbers are a non-natural process that are considered by SETI scholars an indication of possible life.

"However," Cirkovic added, "this is the classic understanding of the first contact which I actually intend to undermine in the present paper. I argue — after some of the SETI ‘founding fathers,’ notably Nikolai Kardashev — that we are more likely to detect an anomalous astrophysical phenomenon, which would be a signpost of massive engineering effort by extraterrestrial intelligence.”

He added that in recent years the SETI community has said it expects contact to come through detecting one of these engineering signatures rather than through a radio signal. Cirkovic and some other experts call this "Dysonian SETI", after a 2011 paper that Cirkovic co-authored and was led by Robert Bradbury of the Astronomical Observatory of Belgrade.

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Giant ‘Rogue’ Planets Are Less Common Than Scientists Thought

Rogue planet microlensing event
There probably aren't nearly as many giant planets zooming alone through the Milky Way galaxy as scientists had thought, a new study reports.

Previous research had suggested that huge "rogue" or "unbound" worlds, which have no discernible host star, are extremely common in the Milky Way, perhaps outnumbering stars by a factor of 2 to 1. But that's probably not the case, according to the new study.

"We found that Jupiter-mass [rogue] planets are at least 10 times less frequent than previously thought," study lead author Przemek Mróz, a researcher at the Warsaw University Observatory in Poland, told Space.com via email.

Astronomers think most rogue planets were likely booted out of their native solar systems by interactions with neighboring planets. Scientists generally hunt for these lonely worlds using a technique called gravitational microlensing, which involves watching for a foreground object to pass in front of a distant star. When this happens, the closer body's gravity bends and magnifies the star's light, in ways that can reveal clues about the foreground object's mass and other characteristics.

A 2011 study, based on 474 microlensing events detected by a telescope in New Zealand, estimated that gas-giant rogue worlds are nearly twice as common as main-sequence ("normal") stars in the Milky Way. (The number of stars in our galaxy is a matter of debate, with estimates ranging from 100 billion to 1 trillion.)

In the new study, Mróz and his team analyzed a much bigger data set — more than 2,600 microlensing events that were detected between 2010 and 2015 by the Optical Gravitational Lensing Experiment (OGLE). This survey, which is run by researchers at the University of Warsaw, depends primarily on observations made at the Las Campanas Observatory in Chile.

The researchers determined that the Milky Way likely hosts a maximum of one Jupiter-like rogue for every four main-sequence stars — still a lot, to be sure, but not nearly as many as the previous study had suggested.

The new results make sense on a number of levels, Mróz said.

"Our new microlensing observations are in agreement with theoretical expectations on the frequency of free-floating Jupiters and with infrared surveys for planetary-mass objects in star-forming regions," he said.

Intriguingly, the OGLE survey also spotted a few extremely brief microlensing events, which Mróz said were likely caused by much smaller worlds — ones about the size of Earth, or just a bit bigger.

"Because our sensitivity to such short events was very low, free-floating Earths should be very common, perhaps more frequent than stars, but we are unable to provide a precise number owing to [the] small number of detections," he told Space.com.

Increasing the number of ground-based microlensing detections would give astronomers a somewhat better understanding of the population of small rogue planets, Mróz said. But big gains may have to wait for future space observatories, such as Europe's Euclid mission and NASA's Wide-Field Infrared Survey Telescope (WFIRST).

Read more at Seeker

How Cow Antibodies Are Helping Scientists Develop an HIV Vaccine

Researchers have long sought to develop an effective HIV vaccine. Several treatments have undergone clinical trials, but the only one that’s been even slightly successful, a 2009 study in Thailand, lowered HIV infection rates by only 30 percent.

But scientists haven’t given up hope.

An effective HIV vaccine could be “transformative,” Anthony Fauci, the director of the National Institute of Allergy and Infectious Disease, said in May. Fauci said modeling from the National Institutes of Health showed that even if a vaccine was only 50 percent effective, it could reduce the number of people living with HIV by 36 percent around the world in 15 years.

Last week, researchers released a study showing progress toward developing an effective vaccine. In their paper, which was published in the journal Nature, they describe their success in prompting a quick immune response to HIV — at least in four cows.

While it may seem a big leap from cows to humans, scientists are encouraged by the results.

Vaccines are made from the same germs that cause a disease. A vaccine is potent enough to prompt an immune response, but not so strong that it causes a recipient to become sick. When exposed to small amounts of a virus, a person’s immune system produces antibodies, which are proteins designed to kill the virus. Even after the virus goes away, the immune cells “remember” it and are able to produce antibodies quickly if a person is exposed to the virus again.

This tried-and-true method, which has helped to combat polio, measles, and the flu, hasn’t worked with HIV because the virus replicates very quickly, leading to dozens of different strains and substrains, and can remain latent in the body for long periods of time.

Antibodies that successfully combat HIV do exist, but only in about 10-20 percent of people infected with HIV. And they often take a long time to develop. When exposed to most viruses, people produce antibodies within a few days. But with HIV, it often takes more than two years.

A man is injected with a potential vaccine during phase III of a HIV vaccine in Thailand.
“One of, if not the major challenge in development of a safe and effective HIV vaccine, is the inability to elicit broadly neutralizing antibodies in humans,” Wayne Koff, president and CEO of the Human Vaccines Project, said in an email. Koff was not affiliated with the new study.

The goal of developing an effective vaccine hinges on prompting a person’s immune system to begin quickly producing what are called broadly neutralizing antibodies (bNAbs) in order to fight off infection.

And that’s where the cows come in.

The researchers, supported by NIH, thought cows might yield insights on fighting HIV when they looked at the structure of human bNAbs that were produced by people with long-term HIV infections. Specifically, they looked at a looped area on the antibodies called HCDR3.

One of the distinct features of the HIV virus is that it is surrounded by a thick envelope of sugars, called the glycan shield, that is hard for normal-sized antibodies to penetrate. The scientists realized that in the small percent of humans that do produce HIV bNAbs those antibodies have extra-long HCDR3 loops that can pierce through the glycan shield.

Antibodies in cows also have naturally long HCDR3 loops, though no one is quite sure why. One theory is, because cows have multiple stomachs with lots of bacteria, they need extra-powerful antibodies to protect them from infection.

The researchers injected the four cows with an HIV immunogen, a molecule that can prompt the HIV immune response. To their surprise, not only did the cows produce HIV bNAbs, but they produced them quickly — within 35 to 50 days. At just over a year, one cow produced bNAbs against 117 strains of HIV.

Read more at Seeker

NASA Posts Archive of Flight Test Videos on YouTube

A Lunar Lander Vehicle Flight with astronaut Neil Armstrong
Aviation geeks rejoice: There’s a whole new way to waste time.

NASA is marking 70 years of advanced aircraft testing by releasing a trove of old video from its Dryden Flight Research Center, the longtime home of the space agency’s atmospheric flight research.

The center, which was renamed for Apollo 11 commander Neil Armstrong in 2014, has posted dozens of short clips on its YouTube page this month. They include old films recently digitized as well as already-online video that has been moved to a more-accessible home, said Leslie Williams, a spokeswoman for the facility.

“The server that held those movies was becoming antiquated,” Williams said. “One of the best ways to preserve that video so other people could see it was to put it out on YouTube.”

The Armstrong center shares space with Edwards Air Force Base in the Mojave Desert east of Los Angeles. Established in 1946, it predates NASA and even the US Air Force, which was created in 1947 — the same year the first test flights were conducted.

It’s the home of the X-planes — high-speed, high-altitude experimental aircraft designed to push the limits of flight. They included the X-1, in which Chuck Yeager made the first supersonic flight in 1947, to the unmanned, 12-foot-long X-43, which hit nearly 7,000 mph in 2004. The latest, the X-57, is designed to test how well cleaner, quieter electric motors will work on manned aircraft.

The mostly-silent clips include footage of Armstrong himself, demonstrating a lunar lander trainer for reporters before his 1969 moon mission. You can watch test pilot Scott Crossfield descend from the bomb bay of a B-29 into the Douglas D-558 rocket plane slung underneath, shortly before it’s dropped from the mother ship. And there several clips of the X-15 space plane, in which several Air Force pilots earned astronaut wings for flights that topped 350,000 feet.

There were duds, too, like the X-3, a needle-nosed, stubby-winged craft nicknamed the Stiletto, which never lived up to its high-speed billing; and the XB-70 Valkyrie, a Mach 3 bomber design from the early 1960s. When the Pentagon passed on the Valkyrie, the two prototypes became test models for a future supersonic airliner.

And there are several lifting-body craft like the X-24, HL-10, and M2 series, which were steppingstones in the development of the space shuttles. It was a 1967 lifting-body crash, not included in this batch of video, that was featured in the opening credits of the 1970s television series “The Six Million Dollar Man.”

Read more at Seeker

Jul 23, 2017

Ultrathin device harvests electricity from human motion

Vanderbilt undergraduate Thomas Metke demonstrates the ultrathin energy harvesting device which is taped across his elbow. As he flexes his arm the current the device generates is displayed on the computer display.
Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting.

A new, ultrathin energy harvesting system developed at Vanderbilt University's Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.

"In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment," said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.

The new energy harvesting system is described in a paper titled "Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets" published Jun.21 online by the journal ACS Energy Letters.

"This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint's advances in materials and energy harvesting," observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device's development.

Currently, there is a tremendous amount of research aimed at discovering effective ways to tap ambient energy sources. These include mechanical devices designed to extract energy from vibrations and deformations; thermal devices aimed at pulling energy from temperature variations; radiant energy devices that capture energy from light, radio waves and other forms of radiation; and, electrochemical devices that tap biochemical reactions.

"Compared to the other approaches designed to harvest energy from human motion, our method has two fundamental advantages," said Pint. "The materials are atomically thin and small enough to be impregnated into textiles without affecting the fabric's look or feel and it can extract energy from movements that are slower than 10 Hertz -- 10 cycles per second -- over the whole low-frequency window of movements corresponding to human motion."

Doctoral students Nitin Muralidharan and Mengya Li co-led the effort to make and test the devices. "When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz," said Muralidharan.

Extracting usable energy from such low frequency motion has proven to be extremely challenging. For example, a number of research groups are developing energy harvesters based on piezoelectric materials that convert mechanical strain into electricity. However, these materials often work best at frequencies of more than 100 Hertz. This means that they don't work for more than a tiny fraction of any human movement so they achieve limited efficiencies of less than 5-10 percent even under optimal conditions.

"Our harvester is calculated to operate at over 25 percent efficiency in an ideal device configuration, and most importantly harvest energy through the whole duration of even slow human motions, such as sitting or standing," Pint said.

The Vanderbilt lab's ultrathin energy harvester is based on the group's research on advanced battery systems. Over the past 3 years, the team has explored the fundamental response of battery materials to bending and stretching. They were the first to demonstrate experimentally that the operating voltage changes when battery materials are placed under stress. Under tension, the voltage rises and under compression, it drops.

The team collaborated with Greg Walker, associate professor of mechanical engineering, who used computer models to validate these observations for lithium battery materials. Results of the study were published Jun. 27 in the journal ACS Nano in an article titled "The MechanoChemistry of Lithium Battery Electrodes."

These observations led Pint's team to reconstruct the battery with both positive and negative electrodes made from the same material. Although this prevents the device from storing energy, it allows it to fully exploit the voltage changes caused by bending and twisting and so produce significant amounts of electrical current in response to human motions.

The lab's initial studies were published in 2016. They were further inspired by a parallel breakthrough by a group at Massachusetts Institute of Technology who produced a postage-stamp-sized device out of silicon and lithium that harvested energy via the effect Pint and his team were investigating.

In response, the Vanderbilt researchers decided to go as thin as possible by using black phosphorus nanosheets: A material has become the latest darling of the 2D materials research community because of its attractive electrical, optical and electrochemical properties.

Because the basic building blocks of the harvester are about 1/5000th the thickness of a human hair, the engineers can make their devices as thin or as thick as needed for specific applications. They have found that bending their prototype devices produces as much as 40 microwatts per square foot and can sustain current generation over the full duration of movements as slow as 0.01 Hertz, one cycle every 100 seconds.

The researchers acknowledge that one of the challenges they face is the relatively low voltage that their device produces. It's in the millivolt range. However, they are applying their fundamental insights of the process to step up the voltage. They are also exploring the design of electrical components, like LCD displays, that operate at lower than normal voltages.

"One of the peer reviewers for our paper raised the question of safety," Pint said. "That isn't a problem here. Batteries usually catch on fire when the positive and negative electrodes are shorted, which ignites the electrolyte. Because our harvester has two identical electrodes, shorting it will do nothing more than inhibit the device from harvesting energy. It is true that our prototype will catch on fire if you put it under a blowtorch but we can eliminate even this concern by using a solid-state electrolyte."

One of the more futuristic applications of this technology might be electrified clothing. It could power clothes impregnated with liquid crystal displays that allow wearers to change colors and patterns with a swipe on their smartphone. "We are already measuring performance within the ballpark for the power requirement for a medium-sized low-power LCD display when scaling the performance to thickness and areas of the clothes we wear." Pint said.

Pint also believes there are potential applications for their device beyond power systems. "When incorporated into clothing, our device can translate human motion into an electrical signal with high sensitivity that could provide a historical record of our movements. Or clothes that track our motions in three dimensions could be integrated with virtual reality technology. There are many directions that this could go."

Read more at Science Daily

Jupiter’s complex transient auroras

Auroras at Jupiter.
Combined observations from three spacecraft show that Jupiter's brightest auroral features recorded to date are powered by both the volcanic moon Io and interaction with the solar wind.

At Earth, auroras are clearly driven by the solar wind that streams past the planet. But Jupiter's gigantic auroras -- magnitudes more powerful than those on Earth -- are believed to be mainly driven by factors within the Jovian system. Now, by combining observations from three spacecraft, scientists from an international collaboration led by a researcher at the RIKEN Nishina Center for Accelerator-Based Science have shown that the picture is complex -- volcanoes on Io, one of Jupiter's moons -- and the most active volcanic body in the solar system -- are responsible for powering some of Jupiter's brightest auroral features through interactions with the shock wave caused by the arrival of the solar wind.

To perform the study, the group looked at data from three space-based sources -- Japan's Hisaki satellite, an earth-orbiting extreme ultraviolet observatory that was launched into low-earth orbit in 2013, the Juno spacecraft, which entered into orbit around Jupiter in July 2016, and the Hubble Space Telescope, which took high-resolution far ultraviolet photos of Jupiter as Juno entered into orbit. By combining the data from the three spacecraft -- including snapshots taken by Hisaki at ten-minute intervals for a period of more than six months, the team was able to more precisely map out the process through which the sulfur gas emerging from Io's powerful volcanoes is stored in the area far from Jupiter, transiently accelerated, transferred toward Jupiter, and channeled into Jupiter's polar region where it drives the aurora. These findings were detected during a "transient brightening" of Jupiter's aurora -- with the phenomenon moving from the polar region toward the equator -- that was detected in May 2016, as Juno was approaching. The data showed that the energy from Io's gas emission was somehow transferred toward Jupiter at a speed approaching 400 to 800 kilometers per second in the equatorial region of the space around Jupiter.

Previous observations had been made combining the data from Hisaki and the HST had concluded that the solar wind had little to do with the transient auroras. "What is special about our observations," says lead author Tomoki Kimura, a Special Postdoctoral Researcher at RIKEN, "is that we were able to time the observations with the arrival of the Juno spacecraft into Jovian orbit. It turns out that Juno detected a shock wave originating from the solar wind, and this led us to infer that the solar wind was, along with Io, playing a role in the process by driving the energy toward Jupiter."

In the past, it was generally considered that the magnetic field of a rotating astronomical body is powerful enough to completely dominate azimuthal movements of energy and mass near it, but the team's findings challenge this assumption, as the energy seems to move from the area far from Jupiter toward Jupiter.. Moreover, this process seems to hold for other rotating bodies such as neutron stars.

Read more at Science Daily

Jul 22, 2017

The moon is front and center during a total solar eclipse

In the lead-up to a total solar eclipse, most of the attention is on the sun, but Earth's moon also has a starring role.
In the lead-up to a total solar eclipse, most of the attention is on the sun, but Earth's moon also has a starring role.

"A total eclipse is a dance with three partners: the moon, the sun and Earth," said Richard Vondrak, a lunar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It can only happen when there is an exquisite alignment of the moon and the sun in our sky."

During this type of eclipse, the moon completely hides the face of the sun for a few minutes, offering a rare opportunity to glimpse the pearly white halo of the solar corona, or faint outer atmosphere. This requires nearly perfect alignment of the moon and the sun, and the apparent size of the moon in the sky must match the apparent size of the sun.

On average, a total solar eclipse occurs about every 18 months somewhere on Earth, although at any particular location, it happens much less often.

The total eclipse on Aug. 21, 2017, will be visible within a 70-mile-wide path that will cross 14 states in the continental U.S. from Oregon to South Carolina. Along this path of totality, the umbra, or dark inner shadow, of the moon will travel at speeds of almost 3,000 miles per hour in western Oregon to 1,500 miles per hour in South Carolina.

In eclipse maps, the umbra is often depicted as a dark circle or oval racing across the landscape. But a detailed visualization created for this year's eclipse reveals that the shape is more like an irregular polygon with slightly curved edges, and it changes as the shadow moves along the path of totality.

"With this new visualization, we can represent the umbral shadow with more accuracy by accounting for the influence of elevation at different points on Earth, as well as the way light rays stream through lunar valleys along the moon's ragged edge," said NASA visualizer Ernie Wright at Goddard.

This unprecedented level of detail was achieved by coupling 3-D mapping of the moon's surface, done by NASA's Lunar Reconnaissance Orbiter, or LRO, with Earth elevation information from several datasets.

LRO's mapping of the lunar terrain also makes it possible to predict very accurately when and where the brilliant flashes of light called Baily's Beads or the diamond-ring effect will occur. These intense spots appear along the edge of the darkened disk just before totality, and again just afterward, produced by sunlight peeking through valleys along the uneven rim of the moon.

In the very distant future, the spectacular shows put on by total solar eclipses will cease. That's because the moon is, on average, slowly receding from Earth at a rate of about 1-1/2 inches, or 4 centimeters, per year. Once the moon moves far enough away, its apparent size in the sky will be too small to cover the sun completely.

Read more at Science Daily

North American monsoon storms fewer but more extreme

Monsoon season now brings more extreme wind and rain to central and southwestern Arizona than in the past, according to new research led by the University of Arizona.

Although there are now fewer storms, the largest monsoon thunderstorms bring heavier rain and stronger winds than did the monsoon storms of 60 years ago, the scientists report.

"The monsoon is the main severe weather threat in Arizona. Dust storms, wind, flash flooding, microbursts -- those are the things that are immediate dangers to life and property," said co-author Christopher Castro, a UA associate professor of hydrology and atmospheric sciences.

The researchers compared precipitation records from 1950-1970 to those from 1991-2010 for Arizona. The researchers also used those records to verify that their climate model generated realistic results.

"This is one of the first studies to look at long-term changes in monsoon precipitation," Castro said. "We documented that the increases in extreme precipitation are geographically focused south and west of the Mogollon Rim -- and that includes Phoenix."

The region of Arizona with more extreme storms includes Bullhead City, Kingman, the Phoenix metropolitan area, the Colorado River valley and Arizona's low deserts, including the towns of Casa Grande, Gila Bend, Ajo, Lukeville and Yuma.

The Tohono O'odham Reservation, Luke Air Force Base, the Barry Goldwater Air Force Range and the Yuma Proving Ground are also in the region with more extreme monsoon weather.

Tucson is just outside of the zone with more extreme storms.

Having less frequent but more intense storms is consistent with what is expected throughout the world due to climate change, Castro said.

"Our work shows that it certainly holds true for the monsoon in Arizona," he said.

When the researchers compared the results from climate and weather models to the actual observations, the model with a resolution of less than 1.5 miles (2.5 km) accurately reproduced the precipitation data. The models with resolutions of 10 miles or more did not.

"You just can't trust coarser simulations to represent changes in severe weather. You have to use the high-resolution model," Castro said.

First author Thang M. Luong conducted the research as part of his doctoral work at the UA. He is now a postdoctoral researcher at King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.

The paper, "The More Extreme Nature of North American Monsoon Precipitation in the Southwestern U.S. as Revealed by a Historical Climatology of Simulated Severe Weather Events," by Luong, Castro, Hsin-I Chang and Timothy Lahmers of the UA Department of Hydrology and Atmospheric Sciences and David K. Adams and Carlos A. Ochoa-Moya of the Universidad Nacional Autónoma de México, México D.F. was published July 3 in the early online edition of the Journal of Applied Meteorology and Climatology.

The U.S. Department of Defense Strategic Environmental Research and Development Program and the Universidad Nacional Autónoma de México PAPIIT funded the research.

The researchers wanted to identify risks from warm-season extreme weather, especially those to Department of Defense installations in the American Southwest.

Existing global and regional climate change models don't represent the North American monsoon well in either seasonal forecasts or climate projections, the research team wrote.

Looking at the average precipitation over the entire monsoon season doesn't show whether monsoon storms are becoming more severe now compared with 60 years ago, Castro said.

Therefore Luong, Castro and their colleagues looked for extreme rainfall events during 1950-1970 as compared with 1991-2010. Average precipitation was about the same, but 1991-2011 had more storms with very heavy rain.

"What's going on in the changes to the extremes is very different from what goes on in the changes to the mean," Castro said. "Big storms, heavy flooding -- we found out those types of extreme precipitation events are becoming more intense and are becoming more intense downwind of the mountain ranges."

The team tested a common computer model of the atmosphere to try to replicate the historical changes in monsoon storm intensity. The model, similar to one used by the National Weather Service for forecasts, produces results similar to what would be observed on radar or satellite imagery by realistically simulating the physical structure of monsoon thunderstorms.

A key innovation of the UA research was the level of detail -- the team tested several different levels of resolution. Only by using the high resolution of 1.5 miles (2.5 km) could the model replicate the actual rainfall recorded for the two 20-year periods being compared.

The recorded data showed only rainfall. The high-resolution models indicated rainier monsoon storms were accompanied by higher winds and more downbursts.

"Because the models get the precipitation right, it gives us confidence that the models get the winds right too," Castro said.

He said that in Phoenix, monsoon storms used to be late in the evening but are now happening earlier.

Read more at Science Daily

Jul 21, 2017

In saliva, clues to a 'ghost' species of ancient human

Neanderthal. In saliva, scientists have found hints that a "ghost" species of archaic human may have contributed genetic material to ancestors of people living in Sub-Saharan Africa today.
In saliva, scientists have found hints that a "ghost" species of archaic humans may have contributed genetic material to ancestors of people living in Sub-Saharan Africa today.

The research adds to a growing body of evidence suggesting that sexual rendezvous between different archaic human species may not have been unusual.

Past studies have concluded that the forebears of modern humans in Asia and Europe interbred with other early hominin species, including Neanderthals and Denisovans. The new research is among more recent genetic analyses indicating that ancient Africans also had trysts with other early hominins.

"It seems that interbreeding between different early hominin species is not the exception -- it's the norm," says Omer Gokcumen, PhD, an assistant professor of biological sciences in the University at Buffalo College of Arts and Sciences.

"Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva," he says. "When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern day Sub-Saharan African populations."

The research was published on July 21 in the journal Molecular Biology and Evolution. The study was led by Gokcumen and Stefan Ruhl, DDS, PhD, a professor of oral biology in UB's School of Dental Medicine.

A tantalizing clue in saliva

The scientists came upon their findings while researching the purpose and origins of the MUC7 protein, which helps give spit its slimy consistency and binds to microbes, potentially helping to rid the body of disease-causing bacteria.

As part of this investigation, the team examined the MUC7 gene in more than 2,500 modern human genomes. The analysis yielded a surprise: A group of genomes from Sub-Saharan Africa had a version of the gene that was wildly different from versions found in other modern humans.

The Sub-Saharan variant was so distinctive that Neanderthal and Denisovan MUC7 genes matched more closely with those of other modern humans than the Sub-Saharan outlier did.

"Based on our analysis, the most plausible explanation for this extreme variation is archaic introgression -- the introduction of genetic material from a 'ghost' species of ancient hominins," Gokcumen says. "This unknown human relative could be a species that has been discovered, such as a subspecies of Homo erectus, or an undiscovered hominin. We call it a 'ghost' species because we don't have the fossils."

Given the rate that genes mutate during the course of evolution, the team calculated that the ancestors of people who carry the Sub-Saharan MUC7 variant interbred with another ancient human species as recently as 150,000 years ago, after the two species' evolutionary path diverged from each other some 1.5 to 2 million years ago.

Why MUC7 matters

The scientists were interested in MUC7 because in a previous study they showed that the protein likely evolved to serve an important purpose in humans.

In some people, the gene that codes for MUC7 holds six copies of genetic instructions that direct the body to build parts of the corresponding protein. In other people, the gene harbors only five sets of these instructions (known as tandem repeats).

Prior studies by other researchers found that the five-copy version of the gene protected against asthma, but Gokcumen and Ruhl did not see this association when they ran a more detailed analysis.

The new study did conclude, however, that MUC7 appears to influence the makeup of the oral microbiome, the collection of bacteria within the mouth. The evidence for this came from an analysis of biological samples from 130 people, which found that different versions of the MUC7 gene were strongly associated with different oral microbiome compositions.

Read more at Science Daily

Best measure of star-forming material in galaxy clusters in early universe

The Tadpole Galaxy is a disrupted spiral galaxy showing streams of gas stripped by gravitational interaction with another galaxy. Molecular gas is the required ingredient to form stars in galaxies in the early universe.
The international Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) collaboration based at the University of California, Riverside has combined observations from several of the world's most powerful telescopes to carry out one of the largest studies yet of molecular gas -- the raw material which fuels star formation throughout the universe -- in three of the most distant clusters of galaxies ever found, detected as they appeared when the universe was only four billion years old.

Results were recently published in The Astrophysical Journal Letters. Allison Noble, a postdoctoral researcher at the Massachusetts Institute of Technology, led this newest research from the SpARCS collaboration.

Clusters are rare regions of the universe consisting of tight groups of hundreds of galaxies containing trillions of stars, as well as hot gas and mysterious dark matter. First, the research team used spectroscopic observations from the W. M. Keck Observatory on Mauna Kea, Hawai'i, and the Very Large Telescope in Chile that confirmed 11 galaxies were star-forming members of the three massive clusters. Next, the researchers took images through multiple filters from NASA's Hubble Space Telescope, which revealed a surprising diversity in the galaxies' appearance, with some galaxies having already formed large disks with spiral arms.

One of the telescopes the SpARCS scientists used is the extremely sensitive Atacama Large Millimeter Array (ALMA) telescope capable of directly detecting radio waves emitted from the molecular gas found in galaxies in the early universe. ALMA observations allowed the scientists to determine the amount of molecular gas in each galaxy, and provided the best measurement yet of how much fuel was available to form stars.

The researchers compared the properties of galaxies in these clusters with the properties of "field galaxies" (galaxies found in more typical environments with fewer close neighbors). To their surprise, they discovered that cluster galaxies had higher amounts of molecular gas relative to the amount of stars in the galaxy, compared to field galaxies. The finding puzzled the team because it has long been known that when a galaxy falls into a cluster, interactions with other cluster galaxies and hot gas accelerate the shut off of its star formation relative to that of a similar field galaxy (the process is known as environmental quenching).

"This is definitely an intriguing result," said Gillian Wilson, a professor of physics and astronomy at UC Riverside and the leader of the SpARCS collaboration. "If cluster galaxies have more fuel available to them, you might expect them to be forming more stars than field galaxies, and yet they are not."

Noble, a SpARCS collaborator and the study's leader, suggests several possible explanations: It is possible that something about being in the hot, harsh cluster environment surrounded by many neighboring galaxies perturbs the molecular gas in cluster galaxies such that a smaller fraction of that gas actively forms stars. Alternatively, it is possible that an environmental process, such as increased merging activity in cluster galaxies, results in the observed differences between the cluster and field galaxy populations.

"While the current study does not answer the question of which physical process is primarily responsible for causing the higher amounts of molecular gas, it provides the most accurate measurement yet of how much molecular gas exists in galaxies in clusters in the early universe," Wilson said.

Read more at Science Daily

A wolf's howl in miniature: Researchers discover mice speak similarly to humans

Some mice and rats employ a whistle-like mechanism.
Grasshopper mice (genus Onychomys), rodents known for their remarkably loud call, produce audible vocalizations in the same way that humans speak and wolves howl, according to new research published in Proceedings of the Royal Society B. Grasshopper mice employ both a traditional whistle-like mechanism used by other mice and rats and a unique airflow-induced tissue vibration like that of humans.

Researchers from Northern Arizona University, Midwestern University at Glendale and Ritsumeikan University in Japan used heliox experiments, laryngeal and vocal tract morphological investigations and biomechanical modelling to investigate how grasshopper mice produce spectacular long-distance calls.

"Our findings provide the first evidence of a mouse that produces sound like humans and sets the stage for studies on vocal injuries and aging," said lead author Bret Pasch, NAU assistant professor and Merriam-Powell Center affiliate. "Moreover, the research provides a baseline for a larger comparative analysis of vocalizations in rodents, which comprise more than 40 percent of mammalian diversity but whose many voices remain undiscovered."

Grasshopper mice are predatory rodents that inhabit deserts, grasslands and prairies of the western United States and northern Mexico. Like most mice, grasshopper mice produce ultrasonic vocalizations above the range of human hearing in close-distance social interactions through whistle-like mechanisms.

Unlike other mice, grasshopper mice also produce long-distance audible vocalizations, or advertisement vocalizations. Naturalist Vernon Bailey described the call of grasshopper mice as a "wolf's howl in miniature." Both male and female animals often assume an upright posture and open their mouths widely to generate a loud call that may carry more than 100 meters. Grasshopper mice have relatively large home ranges, so their calls serve as a mechanism to detect mates and competitors across large distances.

Imaging the voice box of grasshopper mice revealed a thin layer of connective tissue and a tiny structure called a vocal membrane previously only described in detail in echolocating bats. In addition, the mice possess a bell-shaped vocal tract, similar in shape to a loudspeaker, which increases vocal intensity, just like opera singers.

From Science Daily

New Kingdom Egypt: The goldsmith’s tomb

A view of the ruins of the town of Sai. Founded by the Egyptians on the island of the same name in the Nile, in what is now Sudan, the town was occupied from 1500 until 1200 BC.
Ludwig-Maximilians-Universitaet (LMU) in Munich Egyptologist Julia Budka is studying the impact of intercultural contacts in Ancient Egypt. Her excavations in Sudan have uncovered a tomb dating to around 1450 BC on the island of Sai in the Nile.

A previously unknown tomb, some 3400 years old, has recently been uncovered on the island of Sai in the River Nile. It was in use for some time and contains the remains of up to 25 persons. Further analysis of the finds could elucidate the multicultural nature of the island's population during this period.

The island was then located in Nubia, which was the primary source of gold for the New Kingdom of the Egyptian Pharaohs at that time. The tomb was most probably built for a master goldsmith by the name of Khnummose, and was discovered during excavations conducted by Julia Budka, Professor of Egyptian Archaeology and Art. Investigation of the tomb's contents and inscriptions has so far revealed that, following the conquest by the Pharaoh Thutmose III of the local African Kerma kingdom of Kerma, the local elites were rapidly integrated by the new regime. The earliest Egyptian-style burials on Sai date to the reign of this king.

Over the past 5 years, Budka has carried out parallel studies on three different Egyptian settlements that were established during the period of the so-called New Kingdom between 1500 und 1200 BC. The excavations on the island of Sai, which lies in what is now the Sudanese section of the Nile, not only provide insights into the relationship between the official representatives of the occupying power and the local Nubian population, they also demonstrate that the island was inhabited for longer than hitherto assumed.

"It had been thought that the settlement on the island was abandoned after the foundation of a new town at Amara West. Our finds, on the other hand, prove that Hornakht, one of Egypt's highest ranking bureaucrats during the reign of Ramses II, not only had his official residence on the island, but was also buried there," says Budka. This clearly shows that the town on Sai survived until about 1200 BC.

From Science Daily

Astronomers Identify the Origin of Peculiar Signals From Nearby Red Dwarf Star

The Arecibo Observatory in Puerto Rico
Distant satellite interference, not alien communications, were the source of signals emanating from Ross 128, a dim star located 11 light-years from Earth.

Astronomers have finally solved the mystery of peculiar signals coming from a nearby star, a story that sparked intense public speculation this week that perhaps, finally, alien life had been found.

It hasn't. The signal, which has been formally named "Weird!" was interference from a distant satellite.

Of course, astronomers said all along that extraterrestrials were quite far at the bottom of the list of possibilities for the signals detected from Ross 128, a dim star known as a red dwarf some 11 light-years away.

To experts, the true mystery was that they couldn't figure out if the bursts were unusual stellar activity, emissions from other background objects, or interference from satellite communications.

"However, many people were more interested in the signals as potential proof of transmissions from an extraterrestrial intelligent civilization," wrote Abel Mendez, director of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo in a blog post Friday, revealing the true nature of the signals.

After further fueling speculation by summoning the world experts in the hunt for life elsewhere in the universe — the SETI Berkeley Research Center at the University of California — the team issued its conclusion.

"We are now confident about the source of the Weird! Signal," Mendez wrote.

"The best explanation is that the signals are transmissions from one or more geostationary satellites."

The signals only appeared around Ross 128 because it is located "close to the celestial equator where many geostationary satellites are placed," Mendez added.

Study of people

He also released the results of an informal survey that he had posted on his website, asking people to weigh in on what they thought the source of the signals was, and whether or not they were scientists well versed in the matter.

"Nearly 800 people participated in this informal survey (including more than 60 astronomers)," he wrote.

The whole group's consensus was that the signals were most likely coming from some story of stellar activity, or some kind of astronomical phenomenon.

Most people discounted the possibility of radio interference or instrumental failures, saying these were least likely. This, Mendez explained, was hardly a scientific approach to the question.

"This is interesting since in the absence of solid information about the signal, most astronomers would think that these were probably the most likely explanation," Mendez wrote.

Furthermore, about one quarter of respondents said "the most likely explanation of the signal was that of a communication with an Extraterrestrial Intelligence (ETI)," he added.

"These results reflect the still high expectations the public maintains on the possibility of contacting ETI."

Read more at Seeker

Jul 20, 2017

Our brains synchronize during a conversation

Scientists measured the movement of their brainwaves simultaneously and confirmed that their oscillations took place at the same time.
The rhythms of brainwaves between two people taking part in a conversation begin to match each other. This is the conclusion of a study published in the magazine Scientific Reports, led by the Basque research centre BCBL. According to scientists, this interbrain synchrony may be a key factor in understanding language and interpersonal communication.

Something as simple as an everyday conversation causes the brains of the participants to begin to work simultaneously. This is the conclusion of a study carried out by the Basque Centre on Cognition, Brain, and Language (BCBL), recently published in the magazine Scientific Reports.

Until now, most traditional research had suggested the hypothesis that the brain "synchronizes" according to what is heard, and correspondingly adjusts its rhythms to auditory stimuli.

Now, the experts from this Donostia-based research centre have gone a step further and simultaneously analysed the complex neuronal activity of two strangers who hold a dialogue for the first time.

The team, led by Alejandro Pérez, Manuel Carreiras and Jon Andoni Duñabeitia, has confirmed by recording cerebral electrical activity- that the neuronal activity of two people involved in an act of communication "synchronize" in order to allow for a "connection" between both subjects.

"It involves interbrain communion that goes beyond language itself and may constitute a key factor in interpersonal relations and the understanding of language," Jon Andoni Duñabeitia explains.

Thus, the rhythms of the brainwaves corresponding to the speaker and the listener adjust according to the physical properties of the sound of the verbal messages expressed in a conversation. This creates a connection between the two brains, which begin to work together towards a common goal: communication.

"The brains of the two people are brought together thanks to language, and communication creates links between people that go far beyond what we can perceive from the outside," added the researcher from the Basque research centre. "We can find out if two people are having a conversation solely by analysing their brain waves."

What is neural synchrony?

For the purposes of the study, the BCBL researchers used 15 dyads of people of the same sex, complete strangers to each other, separated by a folding screen. This ensured that the connection generated was truly thanks to the communication established.

Following a script, the dyads held a general conversation and took turns playing the roles of speaker and listener.

Through electroencephalography (EEG) -- a non-invasive procedure that analyses electrical activity in the brain -- the scientists measured the movement of their brainwaves simultaneously and confirmed that their oscillations took place at the same time.

"To be able to know if two people are talking between themselves, and even what they are talking about, based solely on their brain activity is something truly marvellous. Now we can explore new applications, which are highly useful in special communicative contexts, such as the case of people who have difficulties with communication," Duñabeitia pointed out.

In the future, the understanding of this interaction between two brains would allow for the comprehension and analysis of very complex aspects of the fields of psychology, sociology, psychiatry, or education, using the neural images within an ecological or real-world context.

"Demonstrating the existence of neural synchrony between two people involved in a conversation has only been the first step," confirmed Alejandro Pérez. "There are many unanswered questions and challenges left to resolve."

Pérez further maintains that the practical potential of the study is enormous. "Problems with communication occur every day. We are planning to get the most out of this discovery of interbrain synchronization with the goal of improving communication," he concluded.

Read more at Science Daily

Not under the skin, but on it: Living together brings couples' microbiomes together

You share more than just your living space with your partner.
Couples who live together share many things: Bedrooms, bathrooms, food, and even bacteria. After analyzing skin microbiomes from cohabitating couples, microbial ecologists at the University of Waterloo, in Canada, found that people who live together significantly influence the microbial communities on each other's skin.

The commonalities were strong enough that computer algorithms could identify cohabitating couples with 86 percent accuracy based on skin microbiomes alone, the researchers report this week in mSystems, an open-access journal of the American Society for Microbiology.

However, the researchers also reported that cohabitation is likely less influential on a person's microbial profile than other factors like biological sex and what part of the body is being studied. In addition, the microbial profile from a person's body usually looks more like their own microbiome than like that of their significant other.

"You look like yourself more than you look like your partner," says Ashley Ross, who led the study while a graduate student in the lab of Josh Neufeld.

"Can we link couples back together? The answer is yes, but not a very loud yes," says senior author Neufeld, whose lab focuses on microbial communities and their interactions.

Neufeld and Ross, together with Andrew Doxey, analyzed 330 skin swabs collected from 17 sites on the participants, all of whom were heterosexual and lived in the Waterloo region. Participants self-collected samples with swabs, and sites included the upper eyelids, outer nostrils, inner nostrils, armpits, torso, back, navel, and palms of hands.

Neufeld says the study is the first to identify regions of skin with the most similar microbiomes between partners. They found the strongest similarities on partners' feet.

"In hindsight, it makes sense," says Neufeld. "You shower and walk on the same floor barefoot. This process likely serves as a form of microbial exchange with your partner, and also with your home itself." As a result, partners end up with the same mix.

The analyses revealed stronger correlations in some sites than in others. For example, microbial communities on the inner thigh were more similar among people of the same biological sex than between cohabiting partners. Computer algorithms could differentiate between men and women with 100 percent accuracy by analyzing inner thigh samples alone, suggesting that a person's biological sex can be determined based on that region, but not others.

The researchers also found that the microbial profiles of sites on a person's left side -- like hands, eyelids, armpits, or nostrils -- strongly resemble those on their right side. Of all the swab sites, the least microbial diversity was found on either side of the outer nose.

Ross says previous research had shown that skin microbial communities vary within an individual from region to region, but she wanted to know what other factors -- like cohabitation -- help shape the microbiome. In previous work, she and Neufeld analyzed samples collected from door handles at the University of Waterloo to determine whether buildings could be identified based on their door-handle microbiomes. In the future, she says she hopes to see similar analyses of same-sex couples, or couples of different ethnic backgrounds.

Read more at Science Daily

Use of cognitive abilities to care for grandkids may have driven evolution of menopause

A grandmother's cognitive abilities make a big difference to her grandchildren's future.
Instead of having more children, a grandmother may pass on her genes more successfully by using her cognitive abilities to directly or indirectly aid her existing children and grandchildren. Such an advantage could have driven the evolution of menopause in humans, according to new research published in PLOS Computational Biology.

Women go through menopause long before the end of their expected lifespan. Researchers have long hypothesized that menopause and long post-reproductive lifespan provide an evolutionary advantage; that is, they increase the chances of a woman passing on her genes. However, the precise nature of this advantage is still up for debate.

To investigate the evolutionary advantage of menopause, Carla Aimé and colleagues at the Institute of Evolutionary Sciences of Montpellier developed computer simulations of human populations using artificial neural networks. Then they tested which conditions were required for menopause to emerge in the simulated populations.

Specifically, the research team used the simulations to model the emergence and evolution of resource allocation decision-making in the context of reproduction. Menopause can be considered a resource allocation strategy in which reproduction is halted so that resources can be reallocated elsewhere.

The researchers found that emergence of menopause and long post-reproductive lifespan in the simulated populations required the existence of cognitive abilities in combination with caring for grandchildren. The importance of cognitive abilities rather than physical strength lends support to a previously proposed hypothesis for the evolution of menopause known as the Embodied Capital Model.

Read more at Science Daily

Elephant seals recognize each other by the rhythm of their calls

This photo shows two northern elephant seal males scuffling on the beach in San Mateo, California.
Every day, humans pick up on idiosyncrasies such as slow drawls, high-pitched squeaks, or hints of accents to put names to voices from afar. This ability may not be as unique as once thought, researchers report on July 20 in Current Biology. They find that unlike all other non-human mammals, northern elephant seal males consider the spacing and timing of vocal pulses in addition to vocal tones when identifying the calls of their rivals.

"This is the first natural example where on a daily basis, an animal uses the memory and the perception of rhythm to recognize other members of the population," says first author Nicolas Mathevon, of the Université de Lyon/Saint-Etienne in France. "There have been experiments with other mammals showing that they can detect rhythm, but only with conditioning."

Over several years studying an elephant seal colony in Año Nuevo State Park, California, the researchers were able to recognize many of the individual animals just by the rhythm of their voices, he says. To test whether the elephant seals themselves made those distinctions in the same way, the researchers designed an experiment based on the social behavior of the colony's "beta males," who shy away upon hearing the call of a more powerful "alpha male" but ignore or confront other beta males and still-weaker "peripheral males."

Upon hearing computer-modified alpha male calls with a sped-up or slowed-down tempo or a shifted pitch range, the beta males fled the scene if the alteration was minute enough to be within the individual variation of a particular alpha male's roar but stayed put when confronted with more extreme changes. The divergent responses indicated that the seals were sensitive to both rhythmic and tonal characteristics when identifying potential rivals within the colony.

"It is possible that maybe the ability to perceive rhythm is actually very general in animals," Mathevon says, "but it's extremely important for elephant seals, to the point of survival. Competing for females, the males fight very violently, even to the point of killing one another. So it's very important for them to accurately recognize the voices, to be able to choose the right strategy, to know to avoid a fight with a dominant male, or even to start a fight with an inferior one."

Read more at Science Daily

Explore Mars With NASA Images and Data Visualization of the Red Planet

Have you ever wished you could go to Mars without taking on the long-term commitment and risks associated with spaceflight? Now you can explore the surface of Mars without leaving the comfort of planet Earth, thanks to troves of imagery from NASA spacecraft and a cool data-visualization software called OpenSpace.

With OpenSpace, you can fly over Martian mountaintops and swoop through the deep canyons of Valles Marineris with the highest-resolution views from NASA's Mars Reconnaissance Orbiter (MRO), creating sort of a Google Earth for Mars. And that's just the beginning; the makers of OpenSpace said they aim to ultimately map the entire known universe with dynamic and interactive visualizations created from real scientific data.

Using data and images from the Context Camera (CTX) on MRO and the Mars rovers Spirit and Opportunity, researchers have already mapped 90 percent of the Red Planet's surface down to a resolution of about 20 feet (6 meters) per pixel. Incorporating high-resolution images from the spacecraft's HiRISE camera (High-Resolution Imaging Science Experiment), OpenSpace has allowed researchers to image parts of Mars down to a resolution of about 25 centimeters (10 inches) per pixel. That's 24 times sharper than before.

This view of the Ganges Chasma region on Mars shows mountainous features called light mounds. Westerly winds on Mars have created a wake around the structure on the right that is visible around the dunes at the mountain's base.
NASA and SpaceX have used HiRISE to look at potential landing sites for upcoming robotic missions like the Mars 2020 rover and Red Dragon sample-return mission, because the camera can resolve details in the terrain and determine whether it's safe for a rover to touch down and drive around there. When HiRISE isn't looking at landing sites, scientists use it to study other aspects of the Martian surface.

Since MRO arrived at the Red Planet 11 years ago, HiRISE has taken more than 4,500 stereo images of the Martian surface. The US Geological Survey has so far gotten around to processing only about 380 of these images to incorporate them into a map of the Martian terrain.

That's where OpenSpace comes in. In a partnership with the American Museum of Natural History in New York City and Linköping University in Sweden, researchers and student interns have been working to turn loads of data into stunning, interactive visualizations. "We have figured out the technique where we can do that ourselves with a massive photogrammetry tool kit called the NASA Ames Stereo Pipeline," Carter Emmart, the director of the astrovisualization program at the museum and creative lead of OpenSpace, told Space.com.

Carter Emmart (center), director of astrovisualization at the American Museum of Natural History, worked with Bergen County Academies students Brian Di Paolo, David Song, Vincent Mallet and Janette Levin (left to right) to develop stunning visualizations of Mars with authentic NASA data.
NASA had warned Emmart and his colleagues against working with these images "because they're extremely data intensive," he said, "but we've worked that out with our production systems staff here at the museum and together with the high school students, so we have a pipeline for cherry-picking essentially these interesting areas that have not been processed yet."

With high-resolution, 3D renditions of the Martian landscape, you can make out small surface features like sharp mountain peaks and rocks as small as footballs. You can even find NASA's Curiosity rover and its landing site, where some hardware was left behind, and what's left of the European Space Agency's Schiaparelli lander that crashed on Mars in October.

Since they started working in 2002, Emmart and his student interns have created "a unique visual system for looking at what we call our digital universe — data that essentially goes from the Earth to the macroscales of the universe."

Beyond Mars, the researchers are already planning to build these types of visualizations for Earth's moon, Pluto, Mercury, and Saturn's moons Titan and Enceladus, with the ultimate and ambitious goal of visualizing the entire universe. OpenSpace also visualizes space weather events, like solar flares and coronal mass ejections, which can affect Earth's satellites and other spacecraft throughout the solar system.

Eventually, OpenSpace visualizations will be available on YouTube in the form of 360-degree videos, Emmart said. For now, those who wish to embark on a journey to Mars with OpenSpace can do so at New York's Hayden Planetarium. On Aug. 1, Emmart will give his Mars presentation together with the MARSBAND, a group of musicians who will play live music to accompany the Martian tour.

Read more at Discovery News