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Mon, 08 Feb 2016
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Nebula

Astronomers discover evidence of possible ninth planet on fringes of Solar System

© Caltech/R. Hurt (IPAC)
This artist's conception shows the view from (hypothetical) Planet Nine back towards the Sun
A century after observatory founder Percival Lowell speculated that a 'Planet X' lurks at the fringes of the Solar System, astronomers say that they have the best evidence yet for such a world. They call it Planet Nine.

Orbital calculations suggest that Planet Nine, if it exists, is about ten times the mass of Earth and swings an elliptical path around the Sun once every 10,000 - 20,000 years. It would never get closer than about 200 times the Earth - Sun distance, or 200 astronomical units (au). That range would put it far beyond Pluto, in the realm of icy bodies known as the Kuiper belt.

No one has seen Planet Nine, but researchers have inferred its existence from the way several other Kuiper belt objects (KBOs) move. And given the history of speculation about distant planets (see 'Solving for X'), Planet Nine may end up in the dustbin of good ideas gone wrong.

Info

Newly discovered microplate reveals ancient continents' movements

© NASA Earth Observatory
In areas with the deepest underwater ridges (shown in blue), the Earth’s gravity is lowest.
Tectonic plates may have inched across the Earth's surface to where they are now over the course of billions of years, but they left behind traces of this movement in bumps and gashes under the sea. Now, a new topographic map of the seafloor has helped researchers chronicle when the Indian-Eurasian continent formed as well as find a previously undiscovered microplate that broke off as a result of the event.

NASA's Earth Observatory released the map on Jan. 13, and it reveals the complex topography of the planet's seafloor. By analyzing these underwater peaks and ridges, researchers can decipher how and when the plates that made up the ancient supercontinent Pangaea tore apart about 200 million years ago, resulting in the birth of new ocean crust and the formation of mountain ranges.

The map, which is bright blue and red like a heat map, was compiled by an international team of researchers using a gravity model of the ocean, which is in turn based on altimetry data from the CryoSat-2 and Jason-1 satellites.

Altimetry measures the height of the sea surface from space by timing how long it takes a radar signal to reflect off the ocean and return to the satellite. The subtle highs and lows of the ocean surface mimic both seafloor topography and Earth's gravity field, according to NASA.

Beaker

Cocaine causes brain cells to cannibalize themselves - overstimulates autophagy mechanism

© Penn State
Cocaine triggers overactive autophagy in the brain — making cells cannibalize themselves
Working with mice, researchers at Johns Hopkins have contributed significant new evidence to support the idea that high doses of cocaine kill brain cells by triggering overactive autophagy, a process in which cells literally digest their own insides. Their results, moreover, bring with them a possible antidote, an experimental compound dubbed CGP3466B.

A summary of the study, which also found signs of autophagy in the brain cells of mice whose mothers received cocaine while pregnant, will be published online the week of Jan. 18 in the Proceedings of the National Academy of Sciences.

"We performed 'autopsies' to find out how cells die from high doses of cocaine," says Solomon Snyder, M.D., professor of neuroscience at the Johns Hopkins University School of Medicine. "That information gave us immediate insight into how we might use a known compound to interfere with that process and prevent the damage."

After discovering in 1990 that brain cells use the gas nitric oxide to communicate, Snyder and his research team have spent decades studying its impact. In 2013, the team found that nitric oxide is involved in cocaine-induced cell death through its interactions with GAPDH, an enzyme, but didn't learn how precisely the cells were dying.

Take 2

Gamma rhythms and mental compression: How your brain plays memories in fast forward

A newly discovered mechanism in the brain may explain how we can recall nearly all of what happened on a recent afternoon, or make a thorough plan for how to spend tomorrow, in a fraction of the time that it takes to actually live out the experience.

The findings could advance research into schizophrenia, autism spectrum disorders, Alzheimer's disease, and other disorders where real experiences and ones that exist only in the mind can become distorted.

The mechanism compresses information needed for memory retrieval, imagination, or planning and encodes it on a brain wave frequency that's separate from the one used for recording real-time experiences.

Brain cells share different kinds of information with one another using a variety of different brain waves, analogous to the way radio stations broadcast on different frequencies. Researchers found that one of these frequencies allows us to play back memories, or envision future activities, in fast forward.

Magnify

Shape-shifting worm can develop into five distinct forms, each so different as to look like different species

© MPI f. Developmental Biology
One of the larger, nematode-eating forms of Pristionchus.
Their shapes are so different that they look like five different species.

But genetic studies have shown single species of nematode worm, newly discovered inside figs, can develop into five distinct forms. It is a striking example of physical divergence without genetic divergence.

"We were shocked," says team member Erik Ragsdale of the University of Indiana. "It is remarkable and unusual."

Young Pristionchus nematodes hitch a ride to new figs on the wasps that fertilise the figs. If you look inside the fig soon after the wasps arrive, only a small form of the nematode can be found. It has a simple tube-like mouth for feeding on microbes.

Bug

Scientists conducting world's first arthropod survey find that our homes are just crawling with bugs

© Matt Bertone
False bombardier beetle
You may think your home is your castle, protected from animal invaders by cleaning products, sealed windows, doors, and walls. But scientists who have conducted the world's first survey of arthropods—creepy crawlies like insects, spiders, mites, and centipedes—in U.S. homes, report otherwise.

They randomly sampled the arthropod community in 50 homes in Raleigh, North Carolina, in 2012. The houses ranged in age from 7 to 94 years old, and from 840 to 4833 square feet. Armed with forceps, aspirators, and butterfly nets, the scientists hand-collected specimens—living and dead—from each room. They searched under and behind furniture, along baseboards, ceilings, on shelves, and in closets, amassing a collection of more than 10,000 specimens.

They gathered at least 579 morphospecies—animal types that are difficult to precisely identify—from 304 families. Flies were the most abundant, followed by spiders, beetles, ants, and book lice, whereas fleas and the American cockroach were relatively rare, the scientists report in today's issue of PeerJ.

Some of these, such as the book lice, have a long evolutionary history of living with humans. But the vast majority of specimens were inadvertent visitors, such as gall midges, leafhoppers, and ground beetles (like the false bombardier beetle, pictured above), who had wandered in and were likely looking for the exit.

Smoking

Study finds no link between marijuana use and lowered IQ in teens

© Stanimir G. Stoev/Shutterstock
Roughly half of Americans use marijuana at some point in their lives, and many start as teenagers. Although some studies suggest the drug could harm the maturing adolescent brain, the true risk is controversial. Now, in the first study of its kind, scientists have analyzed long-term marijuana use in teens, comparing IQ changes in twin siblings who either used or abstained from marijuana for 10 years. After taking environmental factors into account, the scientists found no measurable link between marijuana use and lower IQ.

"This is a very well-conducted study ... and a welcome addition to the literature," says Valerie Curran, a psychopharmacologist at the University College London. She and her colleagues reached "broadly the same conclusions" in a separate, nontwin study of more than 2000 British teenagers, published earlier this month in the Journal of Psychopharmacology, she says. But, warning that the study has important limitations, George Patton, a psychiatric epidemiologist at the University of Melbourne in Australia, adds that it in no way proves that marijuana—particularly heavy, or chronic use—is safe for teenagers.

Most studies that linked marijuana to cognitive deficits, such as memory loss and low IQ, looked at a single "snapshot" in time, says statistician Nicholas Jackson of the University of Southern California in Los Angeles, lead author of the new work. That makes it impossible to tell which came first: drug use or poor cognitive performance. "It's a classic chicken-egg scenario," he says.

Beaker

Study finds high doses of cocaine causes brain to eat itself

© Stringer / Reuters
New research suggests that high doses of cocaine can cause the brain to eat itself, according to The Daily Telegraph.

A study carried out by researchers at John Hopkins University found that cocaine can cause a process called "autophagy."The Guardian explained that properly regulated autophagy removes unnecessary debris that is dissolved away by enzymes within cell "pockets."

However, Dr. Prasun Guha, who led the study, explained autophagy by describing a cell as having parallels with as a household generating trash: While "autophagy is the housekeeper that takes out the trash. Usually it's a good thing. But cocaine makes the housekeeper throw away really important things, like mitochondria, which produce energy for the cell."

The test studied the effects of cocaine on mice. After performing postmortems on the mice, the scientists determined that the brains of mice given larger doses of cocaine showed clear signs of autophagy-induced cell death.

Pyramid

Innovative scans of the great pyramid in Egypt reveal new anomalies

© HIP Institute
Researchers of the ScanPyramids mission remove the plates previously placed inside the Bent pyramid to capture cosmic particles.
New anomalies have been detected on Egypt's pyramids by researchers scanning the monuments with innovative technologies, the Ministry of Antiquities said.

According to preliminary results, thermal "points of interest" were observed on the northern facade of the Great Pyramid at Giza, known as Khufu or Cheops, and on the west face of Red pyramid in Dahshur.

The announcement comes at the end of a three-month project to scan four pyramids which are more than 4,500 years old. They include the Great Pyramid, Khafre or Chephren at Giza, the Bent pyramid and the Red pyramid at Dahshur.

Scheduled to last one year, the project, called ScanPyramids, uses a mix of innovative technologies such as infrared thermography, muon radiography, and 3-D reconstruction to identify the presence of unknown internal structures and cavities.

People 2

Hearing emotions: Brain recognizes emotions via sound much faster than by language

Canadian researchers have discovered that it only takes one-tenth of a second for our brains to begin to recognize emotions conveyed by vocalizations.

Investigators say it doesn't matter whether the non-verbal sounds are growls of anger, the laughter of happiness or cries of sadness. We pay more attention when an emotion (such as happiness, sadness or anger) is expressed through vocalizations than we do when the same emotion is expressed in speech.

Scientists at McGill University in Montreal, Canada, believe this process is evolutionary in origin. That is, the speed with which the brain "tags" these vocalizations and the preference given to them compared to language, is due to the potentially crucial role that decoding vocal sounds has played in human survival.

Comment: The sound of your voice influences your emotional state, says researchers