Concussions and Head Impacts May Accelerate Brain Aging

Concussions and even lesser head impacts may speed up the brain's natural aging process by causing signaling pathways in the brain to break down more quickly than they would in someone who has never suffered a brain injury or concussion.

Researchers from the University of Michigan School of Kinesiology and the U-M Health System looked at college students with and without a history of concussion and found changes in gait, balance and in the brain's electrical activity, specifically attention and impulse control, said Steven Broglio, assistant professor of kinesiology and director of the Neurotrauma Research Laboratory.

The declines were present in the brain injury group up to six years after injury, though the differences between the study groups were very subtle, and outwardly all of the participants looked and acted the same.

Broglio, who is also affiliated with Michigan NeuroSport, stressed that the studies lay out a hypothesis where concussions and head impacts accelerate the brain's natural aging process.

The study appears in the July issue of journal Exercise and Sport Sciences Reviews.

"The last thing we want is for people to panic. Just because you've had a concussion does not mean your brain will age more quickly or you'll get Alzheimer's," Broglio said. "We are only proposing how being hit in the head may lead to these other conditions, but we don't know how it all goes together just yet."

Broglio stressed that other factors, such as lifestyle choices, smoking, alcohol consumption, physical exercise, family history and whether or not you "exercise" your brain also impact the brain's aging process. Concussion may only be one small factor.

To begin to understand how concussions might impact brain activity and its signaling pathways, researchers asked the participants to perform certain tasks in front of a computer, and took images of their brains. The brains of the nonconcussed group showed a greater area of electrical activation than the participants with a history of brain injury.

The signaling pathways in our brains are analogous to a five-lane highway. On a new highway, traffic runs smoothly and quickly as all lanes are in top shape. However, during normal aging, the asphalt deteriorates and lanes might become bumpy or even unusable. Traffic slows.

Similarly, our brains start with all pathways clear to transfer electrical signals rapidly. As we age, the brain's pathways break down and can't transfer the information as quickly. Concussive and other impacts to the head may result in a 'pothole' on the brain's highway, causing varying degrees of damage and speeding the pathway's natural deterioration.

"What we don't know is if you had a single concussion in high school, does that mean you will get dementia at age 50?" Broglio said. "Clinically, we don't see that. What we think is it will be a dose response.

"So, if you played soccer and sustained some head impacts and maybe one concussion, then you may have a little risk. If you went on and played in college and took more head balls and sustained two more concussions, you're probably at a little bigger risk. Then if you play professionally for a few years, and take more hits to the head, you increase the risk even more. We believe it's a cumulative effect."

In the next phase of study, researchers will look at people in their 20s, 40s and 60s who did and did not sustain concussions during high school sports. They hope to learn if there is an increasing effect of concussion as the study subjects age.

Read more at Science Daily

Allergies? Your Sneeze Is a Biological Response to the Nose's 'Blue Screen of Death'

New research suggests that sneezing is the body's natural reboot and that patients with disorders of the nose such as sinusitis can't reboot, explaining why they sneeze more often than others.

Who would have thought that our noses and Microsoft Windows' infamous blue screen of death could have something in common? But that's the case being made by a new research report appearing online in The FASEB Journal. Specifically, scientists now know exactly why we sneeze, what sneezing should accomplish, and what happens when sneezing does not work properly. Much like a temperamental computer, our noses require a "reboot" when overwhelmed, and this biological reboot is triggered by the pressure force of a sneeze. When a sneeze works properly, it resets the environment within nasal passages so "bad" particles breathed in through the nose can be trapped. The sneeze is accomplished by biochemical signals that regulate the beating of cilia (microscopic hairs) on the cells that line our nasal cavities.

"While sinusitis rarely leads to death, it has a tremendous impact on quality of life, with the majority of symptoms coming from poor clearance of mucus," said Noam A. Cohen, M.D., Ph.D., a researcher involved in the work from the Department of Otorhinolaryngology-Head and Neck Surgery at the University of Pennsylvania in Philadelphia. "By understanding the process by which patients with sinusitis do not clear mucus from their nose and sinuses, we can try to develop new strategies to compensate for their poor mucus clearance and improve their quality of life."

To make this discovery, Cohen and colleagues used cells from the noses of mice which were grown in incubators and measured how these cells cleared mucus. They examined how the cells responded to a simulated sneeze (puff of air) by analyzing the cells' biochemical responses. Some of the experiments were replicated in human sinus and nasal tissue removed from patients with and without sinusitis. They found that cells from patients with sinusitis do not respond to sneezes in the same manner as cells obtained from patients who do not have sinusitis. The researchers speculate that sinusitis patients sneeze more frequently because their sneezes fail to reset the nasal environment properly or are less efficient at doing so. Further understanding of why sinusitis patients have this difficulty could aid in the development of more effective medications or treatments.

Read more at Science Daily

Later Stone Age Got Earlier Start in South Africa Than Thought

The Later Stone Age emerged in South Africa more than 20,000 years earlier than previously believed -- about the same time humans were migrating from Africa to the European continent, says a new international study led by the University of Colorado Boulder.

The study shows the onset of the Later Stone Age in South Africa likely began some 44,000 to 42,000 years ago, said Paola Villa, a curator at the University of Colorado Museum of Natural History and lead study author. The new dates are based on the use of precisely calibrated radiocarbon dates linked to organic artifacts found at Border Cave in the Lebombo Mountains on the border of South Africa and Swaziland containing evidence of hominid occupation going back 200,000 years.

The Later Stone Age is synonymous to many archaeologists with the Upper Paleolithic Period, when modern humans moved from Africa into Europe roughly 45,000 years ago and spread rapidly, displacing and eventually driving Neanderthals to extinction. The timing of the technological innovations and changes in the Later Stone Age in South Africa are comparable to that of the Upper Paleolithic, said Villa.

"Our research proves that the Later Stone Age emerged in South Africa far earlier than has been believed and occurred at about the same time as the arrival of modern humans in Europe," said Villa. "But differences in technology and culture between the two areas are very strong, showing the people of the two regions chose very different paths to the evolution of technology and society."

A paper on the subject was published July 30 in the Proceedings of the National Academy of Sciences. Co-authors included Sylvain Soriano of the Center National de la Recherche Scientifique, or CNRS, at the University of Paris; Tsenka Tsanova of the Max Planck Institute of Evolutionary Biology in Leipzig, Germany; Ilaria Degano, Jeannette Lucejko and Maria Perla Colombini of the University of Pisa in Italy; Thomas Highham of the University of Oxford in England; Francesco d'Errico of the CNRS at the University of Bordeaux in France; Lucinda Blackwell of the University of Witwatersrand in South Africa; and Peter Beaumont of the McGregor Museum in South Africa.

A companion paper published in PNAS and led by d'Errico reports on organic materials found at Border Cave dating to the Later Stone Age, an indication that the San hunter-gatherer culture first thought to have begun about 20,000 years ago in the region probably emerged as early as 44,000 years ago, said Villa.

Organic artifact assemblages at Border Cave dating to the Later Stone Age included ostrich eggshell beads, thin bone arrowhead points, wooden digging sticks, a gummy substance called pitch that was used to haft, or attach, bone and stone blades to shafts and a lump of beeswax likely used for hafting. The assemblage also included worked tusks of members of the pig family, which likely were used to plane wood, and notched bones that may have been used for counting.

A wooden digging stick from Border Cave dated to about 40,000 years ago was found in association with bored but broken stones likely used to weight such sticks. The sticks and stone weights are similar to digging implements used by women of the prehistoric San hunter-gatherer culture in the region to unearth bulbs and termite larvae, a practice that continued into historic times, said Villa. "These digging sticks from Border Cave are the oldest artifacts of this kind known from South Africa or anywhere else in Africa."

The new PNAS study led by Villa also indicates big changes were occurring in hunting technology during the Later Stone Age at Border Cave, said Villa. They included a shift from spears hafted with stone points -- the main hunting weapon in the Middle Stone Age -- to the likely use of the bow and arrow, a technology that included very thin bone points that probably were tipped with poison, she said.

"The very thin bone points from the Later Stone Age at Border Cave are good evidence for bow and arrow use," said Villa. "The work by d'Errico and colleagues shows that the points are very similar in width and thickness to the bone points produced by San culture that occupied the region in prehistoric times, whose people were known to use bows and arrows with poison-tipped bone points as a way to bring down medium and large-sized herbivores."

Chemical analyses showed the poison used with such bone points was most likely ricinoleic acid, which can be derived from the seeds of castor oil plants and which has been identified as being used in South Africa at least 24,000 years ago. "Such bone points could have penetrated thick hides, but the lack of 'knock-down' power means the use of poison probably was a requirement for successful kills," said Villa.

The lump of beeswax from Border Cave also dating to about 40,000 years ago -- the oldest known beeswax used by humans ever discovered -- was wrapped in plant fibers that may have been similar to fibers used to make the strings for hunting bows, said Villa.

While stone tools continued to be manufactured in the Later Stone Age at Border Cave, stone spear points from the Middle Stone Age gave way to tiny, thin flakes known as microliths that were probably hafted on shafts, much like the bone points, with pitch made from the bark of a common type of coniferous tree found in the region.

While a 2011 study co-authored by Villa and Wil Roebroeks of Leiden University in the Netherlands showed that Neanderthals mastered the manufacture of pitch in Europe 200,000 years ago, it was not a particularly simple task since the process involved burning peeled bark in the absence of air, said Villa. The Later Stone Age inhabitants of South Africa probably dug holes into the ground and inserted bark peels, then lit them on fire and covered the holes tightly with stones. "This is the first time pitch-making is demonstrated in South Africa," said Villa.

The Upper Paleolithic Period in Europe that corresponds to the Later Stone Age in South Africa also spurred complex new technologies that helped humans survive and thrive in much different environments. Artifacts from the Upper Paleolithic included spear-throwers, bone needles with eyelets for sewing furs, bone fishing hooks, bone flutes and even ivory figurines carved from mammoth tusks.

Read more at Science Daily

Presenting the World's Slowest Shark

Greenland sharks are the slowest known sharks, according to a new study that found these sharks move through the water at only about a mile per hour.

The study, which will be published in the September issue of the Journal of Experimental Marine Biology and Ecology, also finds that the sharks are the slowest known fish, when body size is factored in. Greenland sharks just reach top speeds of about 1.7 miles per hour.

"We think that the slow speed of Greenland sharks might be due to low water temperature in the Arctic Ocean," lead author Yuuki Watanabe of the National Institute of Polar Research told Discovery News.

Watanabe and his colleagues used data logging tags to measure the swim speed and tail beat frequency of six free-swimming Greenland sharks. The measurements were then compared to previously recorded data concerning other sharks and fish. (Sharks are considered to be a type of fish.) The mean tail beat frequency for Greenland sharks topped off at 9 beat cycles per minute.

Both this tail beat frequency and the maximum recorded speed for Greenland sharks were the lowest values, when size is considered, across all other known measurements for fish species. Since tail beats reflect muscle-shortening speed, which in turn has been tied to decreasing temperature, the researchers suspect the cold environment of Greenland sharks has turned them into slowpokes.

"Many physiological processes, including muscle shortening speed, slow down with decreasing temperature," Watanabe explained. "This is called the Q10 effect, and it's very strong. Humans do not feel this, because our body temperature is kept high even at cold temperatures. In the case of fishes, body temperature decreases with decreasing ambient temperature, and many physiological processes are depressed."

The slowness of the sharks puts a different twist on the usual marine predator-prey scenario. Many aggressive shark predators zip quickly through the water, enabling them to overtake slower-moving fish and sea mammals.

When the stomach contents of Greenland sharks have been analyzed in the past, scientists have found a lot of fish, but also fresh seals that weren't just scavenged.

"How Greenland sharks hunt seals remains a mystery," Watanabe said. "We hypothesize that sharks hunt seals sleeping in the water because of two reasons. First, seals in captivity can sleep in the water -- at the surface or on the bottom."

"Second," he added, "although how seals sleep in the wild is not known, we in the field observed a seal floating at the surface. At first we thought it was a dead seal, and approached it by boat and actually touched it. Then the seal suddenly started moving and dove down."

There's a good chance, then, that the slow-moving Greenland sharks are simply able to approach a snoozing seal and enjoy a relatively easy dinner.

As for the Greenland shark's own predators, they don't have many because of their very large body size. Some individuals can grow to become 21 feet long, weighing 2,200 pounds. Killer whales might be able to eat them, Watanabe suspects, but Greenland sharks usually stay within deep water that killer whales do not frequent.

Read more at Discovery News

Archeologists Unearth Extraordinary Human Sculpture in Turkey

A beautiful and colossal human sculpture is one of the latest cultural treasures unearthed by an international team at the Tayinat Archaeological Project (TAP) excavation site in southeastern Turkey. A large semi-circular column base, ornately decorated on one side, was also discovered. Both pieces are from a monumental gate complex that provided access to the upper citadel of Kunulua, capital of the Neo-Hittite Kingdom of Patina (ca. 1000-738 BC).

"These newly discovered Tayinat sculptures are the product of a vibrant local Neo-Hittite sculptural tradition," said Professor Tim Harrison, the Tayinat Project director and professor of Near Eastern Archaeology in the University of Toronto's Department of Near and Middle Eastern Civilizations. "They provide a vivid glimpse into the innovative character and sophistication of the Iron Age cultures that emerged in the eastern Mediterranean following the collapse of the great imperial powers of the Bronze Age at the end of the second millennium BC."

The head and torso of the human figure, intact to just above its waist, stands approximately 1.5 metres in height, suggesting a total body length of 3.5 to four metres. The figure's face is bearded, with beautifully preserved inlaid eyes made of white and black stone, and its hair has been coiffed in an elaborate series of curls aligned in linear rows. Both arms are extended forward from the elbow, each with two arm bracelets decorated with lion heads. The figure's right hand holds a spear, and in its left is a shaft of wheat. A crescent-shaped pectoral adorns its chest. A lengthy Hieroglyphic Luwian inscription, carved in raised relief across its back, records the campaigns and accomplishments of Suppiluliuma, likely the same Patinean king who faced a Neo-Assyrian onslaught of Shalmaneser III as part of a Syrian-Hittite coalition in 858 BC.

The second sculpture is a large semi-circular column base, approximately one metre in height and 90 centimetres in diameter, lying on its side next to the human figure. A winged bull is carved on the front of the column and it is flanked by a sphinx on its left. The right side of the column is flat and undecorated, an indication that it originally stood against a wall.

"The two pieces appear to have been ritually buried in the paved stone surface of the central passageway through the Tayinat gate complex," said Harrison. The complex would have provided a monumental ceremonial approach to the upper citadel of the royal city. Tayinat, a large low-lying mound, is located 35 kilometres east of Antakya (ancient Antioch) along the Antakya-Aleppo road.

The presence of colossal human statues, often astride lions or sphinxes, in the citadel gateways of the Neo-Hittite royal cities of Iron Age Syro-Anatolia continued a Bronze Age Hittite tradition that accentuated their symbolic role as boundary zones, and the role of the king as the divinely appointed guardian or gate keeper of the community. By the ninth and eighth centuries BC, these elaborately decorated gateways, with their ornately carved reliefs, had come to serve as dynastic parades, legitimizing the power of the ruling elite. The gate reliefs also formed linear narratives, guiding their audiences between the human and divine realms, with the king serving as the link between the two worlds.

The Tayinat gate complex appears to have been destroyed following the Assyrian conquest of the region in 738 BC, when the area was paved over and converted into the central courtyard of an Assyrian sacred precinct. These smashed and deposited monumental sculptures also include a magnificently carved lion that was discovered last year and Hieroglyphic Luwian-inscribed stelae (stone slabs or pillars used for commemoratives purposes). Together these finds hint of an earlier Neo-Hittite complex that might have once faced the gateway approach.

Read more at Science Daily

Leaning Colosseum of Rome?

"While stands the Coliseum, Rome shall stand; When falls the Coliseum, Rome shall fall; And when Rome falls--the World."

If the Venerable Bede (673-735), the Anglo-Saxon monk and the first English historian who wrote these words (later translated by the poet Lord Byron), heard the news today, he might indeed believe that the end of the world was near.

According to Rome's authorities, the symbol of the Eternal City is in need of support as its south side is 16 inches lower than the north.

The leaning Colosseum might require the kind of structural intervention that straightened the Tower of Pisa.

"The concrete foundation on which the Colosseum rests is like a 42-foot-thick oval doughnut. There could be a stress fracture inside it," Giorgio Monti, from the department of structural engineering at Rome's La Sapienza University, told the Italian daily Corriere della Sera.

The crack in the base below the 2,000-year-old arena may explain why the north and the south side of the monument are no longer horizontally aligned.

"If our doubts are confirmed, we are dealing with two structurally different monuments. At that point, it would be necessary to reunite them," Rossella Rea, the director of the Colosseum, said.

Rea has asked experts from Rome's Sapienza University and the Institute of Environmental Geology and Geoengineering (IGAG) to carry a scientific study on the phenomenon over the next year.

Marking one of the busiest intersections in the city, the Flavian Amphitheater (the Colosseum's proper name) is continuously rocked by vibrations from heavy traffic and a nearby underground metro.

"Following the worrying news, we have begun collecting signatures to support the request for a vast pedestrian area in the streets surrounding the Colosseum and the Roman Forum," the environmental group Legambiente said in a statement.

According to Rea, the same sort of restoration work that saved the Leaning Tower of Pisa more than a decade ago might be needed.

Like the Tower of Pisa, which has been tilting since its construction in 1173, the Colosseum has been built on problematic soil.

The iconic symbol of imperial Rome was built in A.D. 72 by the Flavian emperor Vespasian on the marshy bed of a drained lake. It was opened in A.D. 80 by Vespasian's son Titus with a festival that lasted 100 days and included gladiatorial combats, fights with wild beasts and naval battles for which the arena was flooded.

Read more at Discovery News

Summer Olympics: 1896 vs. 2012

With 116 years separating the first moden Olympics from this year's games, there are bound to be some noticeable changes between the two. Aside from archived photos of the Olympics, one of clearest windows into the first modern Olympics held in 1896 is from G. S. Robertson in an essay titled, "An Englishman at the first modern Olympics" (via http://Longform.org).

Robertson's account of the 1896 paints a picture of an Olympics in its infancy that, while grappling with the challenges of hosting an international competition without the benefits of modern telecommunications or transporation, still manages to capture what would be described in later generations as the Olympic spirit.

If you can manage to squeeze it in between commercial breaks while watching this year's Olympics, Robertson's essay is worth the full read. For those short on time, here are the starkest contrasts between this year's games and the 1896 Olympics:

Entry requirements for the 1896 Olympics: Show up.

Organized by Pierre de Coubertin, considered the father of the modern Olympic movement, the first modern games in Athens in 1896 was meant to include the participation of as many nations from as many corners of the world as possible. As Robertson notes, however, the promoters of the first Olympics had "apparently forgotten that few athletes are classical scholars, and that still fewer have either the time or the money to make so long a voyage."

This meant that a disproportionate number of participants were from the home country, Greece, other nations in continental Europe, and the United States. The United States and Hungary were the only ones to attempt to send an all-around team, according to Robertson. In fact, the first Olympic champion in modern history was an American, triple-jumper James Connolly.

Similarly, although throngs of foreign visitors were expected to swarm Athens for the first Olympics, spectators in Athens were almost exclusively Greek, according to Robertson. Newspapers had estimated 20,000 foreign visitors, but the author puts it closer to 1,000. Still, some 80,000 spectators cheered on the athletes and their victories in 1896.

English was not an official language in the 1896 games.

English and French are the official languages of the Olympic Games. But in 1896, the official book of rules and the program of the Olympics were only printed in French. An unofficial German edition was later printed as well.

According to Robertson, an English-language edition was only printed by a private firm with little lead time ahead of the games. This was partly due to participation of English-language speaking countries as an afterthought by the organizing committee of the first Olympics. This led to a general lack of participation among British athletes.

Despite a general lack of encouragement, American teams turned up in droves fully equipped, due "to the natural enterprise of the American people and to the peculiarly perfect method in which athletics are organized in the United States."

The foundations of the Olympic Charter, the document that guides the Olympic Movement and sets forth the principles by which all participating nations are expected to abide, weren't written down until 1898. Another 10 years would pass before the Charter was published in 1908, bearing the title, "Annuaire du Comité International Olympique." Although the Charter specifies that English and French are the official languages of the movement, the French version of the document supersedes the English edition when there are any discrepancies between the two.

Female athletes did not compete in 1896.

For the first time in Olympic history, the 2012 Olympics will include a female athlete from every participating nation. Saudi Arabia, Qatar and Brunei were the only countries who had yet to field at least one woman on their national teams since the 2008 Olympics in Beijing.

In 1896, however, women weren't allowed to participate in the games at all. Although female athletes were permitted to enter the games four years later, a mere 2 percent of athletes -- 22 out of 997 -- were women competing in five sports: tennis, sailing, croquet, golf and equestrian, according to the International Olympic Committee (IOC) (PDF).

Read more at Discovery News

August Will Be a Blue Moon Month

The month of August brings us not one, but two full moons. The first will kick off the month on Wednesday (Aug.1), and will be followed by a second on Aug. 31.

Some almanacs and calendars assert that when two full moons occur within a calendar month, the second full moon is called a "blue moon."

The full moon that night will likely look no different than any other full moon. But the moon can change color in certain conditions.

After forest fires or volcanic eruptions, the moon can appear to take on a bluish or even lavender hue.  Soot and ash particles, deposited high in the Earth's atmosphere, can sometimes make the moon appear bluish. Smoke from widespread forest fire activity in western Canada created a blue moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons (and even blue suns) worldwide.

Origin of the term

The phrase "once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full moons in the same month is not as uncommon as one might think.  In fact, it occurs, on average, about every 2.66 years.  And in the year 1999, it occurred twice in a span of just three months.

For the longest time no one seemed to have a clue as to where the "blue moon rule" originated.  Many years ago in the pages of Natural History magazine, I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray."  "Perhaps," I suggested, "the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month."

But as innovative as my explanation was, it turned out to be completely wrong.

More mistakes

It was not until that "double blue moon year" of 1999 that the origin of the calendrical term "blue moon" was at long last discovered.  It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a blue moon.

But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that's now popularly accepted as the definition of a blue moon.   

This time around, the moon will turn full on Aug. 31 at 9:58 a.m. Eastern Daylight Time (6:58 a.m. Pacific Standard Time), making it a blue moon.

However, there is an exception: for those living in the Kamchatka region of the Russian Far East as well as in New Zealand, that same full moon occurs after midnight, on the calendar date of Sept. 1. So in these regions of world, this will not be the second of two full moons in August, but the first of two full moons in September. So, if (for example) you reside in Petropavlovsk-Kamchatsky or Christchurch, you'll have to wait until September 30 to declare that the moon is "officially" blue.

Blue Moon/New Moon

While we've assigned the name blue moon to the second full moon of the month, it seems that we have no such name for the second new moon of the month.  Nonetheless, these opposing phases seem to be connected with each other. For if two new moons occur within a specific month, then in most cases, four years later, two full moons will also occur in that very same month.

Read more at Discovery News

Immortality for Humans by 2045

A Russian mogul wants to achieve cybernetic immortality for humans within the next 33 years. He's pulled together a team intent on creating fully functional holographic human avatars that house our artificial brains. Now he's asking billionaires to help fund the advancements needed along the way.

The man behind the 2045 Initiative, described as a nonprofit organization, is a Russian named Dmitry Itskov. The ambitious timeline he's laid out involves creating different avatars. First a robotic copy that's controlled remotely through a brain interface. Then one in which a human brain can be transplanted at the end of life. The next could house an artificial human brain, and finally we'd have holographic avatars containing our intelligence much like the movie "Surrogates."

Gizmag's Dario Borghino wisely warned that "one must be careful not to believe that improbable technological advances automatically become more likely simply by looking further away in the future." And in the grand scheme of things, 2045 is not that far away. So just how likely is it that this project will succeed? For more insight, let's check in with Ted Williams. Oh, wait.

Recently Itskov published an open letterto the Forbes world's billionaires list telling them that they have the ability to finance the extension of their own lives up to immortality. He writes that he can prove the concept's viability to anyone who's skeptical and will coordinate their personal immortality projects for free. PopSci's Clay Dillowdescribed Itskov in March as a 31-year-old media mogul, but I couldn't find a detailed biography for him.

Read more at Discovery News

Magnetic Field, Mantle Convection and Tectonics

On a time scale of tens to hundreds of millions of years, the geomagnetic field may be influenced by currents in the mantle. The frequent polarity reversals of Earth's magnetic field can also be connected with processes in the mantle. These are the research results presented by a group of geoscientists in the new advance edition of Nature Geoscience on July 29th.

The results show how the rapid processes in the outer core, which flows at rates of up to about one millimeter per second, are coupled with the processes in the mantle, which occur more in the velocity range of centimeters per year.

The international group of scientists led by A. Biggin of the University of Liverpool included members of the GFZ German Research Centre for Geosciences, the IPGP Paris, the universities of Oslo and Utrecht, and other partners.

It is known that Earth's magnetic field is produced by convection currents of an electrically conducting iron-nickel alloyin the liquid core, about 3,000 kilometers below Earth's surface. The geomagnetic field is highly variable, there are changes in Earth's magnetic field on a multitude of spatial and temporal scales. Above the liquid outer core is the mantle, the rock in which behaves plastically deformable due to the intense heat and high pressure. At the boundary between Earth's core and mantle at 2900 km depth there is an intense heat exchange, which is on the one hand directed from Earth's core into the mantle. On the other hand, processes within Earth's mantle in turn also affect the heat flow. The interesting question is how the much slower flow in the solid mantle influences the heat flow and its spatial distribution at the core-mantle boundary, and how this will affect the Earth's magnetic field which is produced due to the much faster currents in Earth's core.

Key variable heat transfer

"The key variable is the heat flow. A cooler mantle accelerates the flow of heat from the hot core of Earth, and in this way alters the also heat-driven convection in Earth's core," said Bernhard Steinberger of the GFZ German Research Centre for Geosciences. "Ocean floor sinking into the mantle due to tectonic processes can lead to cooling in the mantle. They cause at these sites an increased heat flow into the cooler parts, namely until they have been heated to the ambient temperature." That might take several hundred million years, however.

Conversely, the hot core of Earth leads to the ascent of heated rocks in form of large bubbles, so-called mantle plumes that separate from the core-mantle boundary and make their way up to the surface of Earth. This is how Hawaii came into existence. This increases the local heat flux out of Earth's core and in turn modifies the generator of the geomagnetic field.

Reversals of the magnetic field

In Earth's history, polarity reversals of the geomagnetic field are nothing extraordinary. The most recent took place only 780 000 years ago, geologically speaking a very short period of time. The research team was able to determine that in the period of 200 to 80 million years before present, reversals initially happened more often, namely up to ten times in hundred million years. "Surprisingly, these reversals stopped about 120 million years ago and were absent for nearly 40 million years," explains GFZ scientist Sachs. Scientists presume that the reason for this is a concurrent reorientation of the whole mantle and crust with a shift in the geographic and magnetic poles of about 30°. Known as "true polar wander," thisprocess is caused by a change in density distribution in the mantle. If it increases the heat flux in equatorial regions, it would presumably lead to more frequent field reversals, if it decreases it, the field reversal might not occur.

Read more at Science Daily