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Why are screams so spine-tingling? Scans reveal they activate the same 'fear circuits' in the brain as smoke alarms

A baby's scream will grab our attention no matter what's on the television or happening around us.

And now scientists have learnt why screams are so arresting - and it's not just because they are loud and high-pitched.

Screams activate 'fear circuits' in our brain because they have a subjective quality called 'roughness' where they quickly switch, or 'modulate', from loud to soft.
Image
© Corbis
Using an MRI scanner, researchers analysed the brains of people listening to recorded screams (Janet Leigh is shown screaming in a grab from the 1960 film Psycho). The scans revealed that the sound activates the amygdala region of the brain, which is typically associated with our fear response
This is what helps give them their jagged, jarring quality that set our nerves on edge.

The same quality of 'roughness' is also found in burglar and car alarms - suggesting engineers may have hit on the feature through trial and error.

Comment: See also: Animal Screams Manipulate Movie Audiences


Comet 2

Meteorite impacts in ancient oceans may have formed DNA building blocks

© Dr. Yoshihiro Furukawa
These are chematics of nucleobases formation by meteorite impact on earth.
A new study shown that meteorite impacts on ancient oceans may have created nucleobases and amino acids. Researchers from Tohoku University, National Institute for Materials Science and Hiroshima University discovered this after conducting impact experiments simulating a meteorite hitting an ancient ocean.

With precise analysis of the products recovered after impacts, the team found the formation of nucleobases and amino acids from inorganic compounds. The research is reported this week in the journal Earth and Planetary Science Letters.

Comment: With the increased frequency of meteors entering our atmosphere in recent years, one might wonder what they might be bringing with them, and the effects on earth of their overhead airbursts and impacts.


Snowflake Cold

Solar activity is declining - what to expect?

© NASA
The Sun by the Atmospheric Imaging Assembly of NASA's Solar Dynamics Observatory.
Is Earth slowly heading for a new ice age? Looking at the decreasing number of sunspots, it may seem that we are entering a nearly spotless solar cycle which could result in lower temperatures for decades. "The solar cycle is starting to decline. Now we have less active regions visible on the sun's disk," Yaireska M. Collado-Vega, a space weather forecaster at NASA's Goddard Space Flight Center, told Phys.org.

But does it really mean a colder climate for our planet in the near future? In 1645, the so-called Maunder Minimum period started, when there were almost no sunspots. It lasted for 70 years and coincided with the well-known "Little Ice Age", when Europe and North America experienced lower-than-average temperatures. However, the theory that decreased solar activity caused the climate change is still controversial as no convincing evidence has been shown to prove this correlation.

Helen Popova, a Lomonosov Moscow State University researcher predicts that if the existing theories about the impact of solar activity on the climate are true, then this minimum will lead to a significant cooling, similar to the one during the Maunder Minimum period. She recently developed a unique physical-mathematical model of the evolution of the magnetic activity of the sun and used it to gain the patterns of occurrence of global minima of solar activity and gave them a physical interpretation.

"Given that our future minimum will last for at least three solar cycles, which is about 30 years, it is possible that the lowering of the temperature will not be as deep as during the Maunder Minimum," Popova said earlier in July. "But we will have to examine it in detail. We keep in touch with climatologists from different countries. We plan to work in this direction."

The solar cycle is the periodic change in the Sun's activity and appearance like changes in the number of sunspots. It has an average duration of about 11 years. The current solar cycle began on in January 2008, with minimal activity until early 2010. The sun is now on track to have the lowest recorded sunspot activity since accurate records began in 1750. The long-term decline in solar activity set in after the last grand solar maximum peaked in 1956.

Comment: See these related articles:


Laptop

DNA could be used to store data more efficiently than computers, scientists find

© Alamy
Internet pioneer Vint Cerf has warned of a 'digital dark age' descending as computer hardware and software becomes obsolete.
DNA could be used to store digital information and preserve essential knowledge for thousands of years, research has shown.

Scientists exploring the archiving potential of DNA conducted a test in which error-free data was downloaded after the equivalent of 2,000 years.

The next challenge is to find a way of searching for information encoded in strands of DNA floating in a drop of liquid.

Lead researcher Dr Robert Grass, from the Swiss Federal Institute of Technology (ETH), said: "If you go back to medieval times in Europe, we had monks writing in books to transmit information for the future, and some of those books still exist. Now, we save information on hard drives, which wear out in a few decades."

DNA has a "language" not unlike the binary code used in computers, said Dr Grass. While a hard drive uses zeros and ones to represent data, the DNA code is written in sequences of four chemical nucleotides, known as A,C,T and G.

But DNA can pack more information into a smaller space, and also has the advantage of durability.

In theory, a fraction of an ounce of DNA could store more than 300,000 terabytes of data, said Dr Grass. And archaeological finds had shown that DNA dating back hundreds of thousands of years can still be sequenced today.

Info

Sweetgrass oil as effective as DEET in repelling mosquitoes

© Andrew Maxwell Phineas Jones, University of Guelph
Sweetgrass, a plant used in traditional medicine, contains compounds that can repel mosquitoes.
Native North Americans have long adorned themselves and their homes with fragrant sweetgrass (Hierochloe odorata), a native plant used in traditional medicine, to repel biting insects, and mosquitoes in particular. Now, researchers report that they have identified the compounds in sweetgrass that keep these bugs at bay.

The team will describe their approach in one of more than 9,000 presentations at the 250th National Meeting & Exposition of the American Chemical Society (ACS), the world's largest scientific society, taking place here through Thursday.

Mosquitoes and other insects remain a pesky part of everyday life in many parts of the world, and their bites are linked to a range of serious diseases, such as malaria. To add to the arsenal of insect repellents, Charles Cantrell, Ph.D., investigates the components of plants used in traditional therapies. "We found that in our search for new insect repellents, folk remedies have provided good leads."

Stock Down

Will humans survive the next mass extinction? Don't count on it!

© Dado Ruvic / Reuters
Death from above. In our future?
Despite populating vast swaths of the planet, and appropriating large amounts natural resources in order to survive, human beings are no more likely to survive a mass extinction event than rare or endangered species, scientists say.

A team from the University of Leeds examining the effects of mass extinctions found that widespread species, like humans, are just as likely to become extinct as less populous ones.

This contrasts with regular circumstances, where a populous species is more likely to survive than a rare or endangered one.

The team of scientists examined the fossil records of vertebrates from the Triassic and Jurassic periods - 252 to 145 million years ago. During this period a mass extinction thought to have been caused by a volcanic eruption wiped out almost 80 percent of all living species and gave rise to the dinosaurs.

Comment: Earth is long past due for its next 'shake-up'. And it's not just the current 'biodiversity crisis caused by human activity'; there is also the cosmic element to consider. In short, our survival is not something we can take for granted. And it is largely outside of our control. Who will take over when we're gone? Surely they'll do a better job with this planet than humanity ever did!


Magnify

Study finds malaria parasites lose drug resistance following changes to health policies

© CC 2.5
Plasmodium sp., Errger der Malaria
Chloroquine (CQ) is a first-line treatment for Plasmodium falciparum infections, which like many other malaria treatments, eventually resulted in the selection of parasites with resistance to the drug. The evolutionary dynamics of antimalarial drug resistance are driven by many factors, including differing transmission contexts and new drug pressures on parasites. Recently, a group of researchers published a study in the Proceedings of the National Academy of Sciences that examined the loss of CQ resistance (CQR) in French Guiana following a health policy change.

To conduct their study, the researchers studied P. falciparum isolates collected between 1994 and 2013 from symptomatic patients in French Guiana. They conducted DNA extraction and phenotyping from samples to compile a database of genetic information about the various strains. Their analysis revealed the presence of a single mutation in the pfcrt allele encoding a substitution associated with a return of parasite susceptibility to CQ.

In 1995, CQ had become ineffective against the prevalent CQR parasite strains in much of French Guiana and surrounding countries, and was officially abandoned as a course of treatment because of poor clinical efficacy. Quinine plus doxycycline became the subsequent treatment through 2007. Researchers used a gene marker, K76T, as a marker for CQ resistance.

Comment: Also see:
Concerns have been raised as, twice before, resistance to the then gold standard anti-malarial drugs - chloroquine and sulfadoxine-pyrimethamine - started in the same region before spreading to South-east Asia and Africa, leading to the deaths of millions of children.

Experts warn millions of lives are at risk as world's most effective malaria drug loses its potency



R2-D2

Computer science: Mass extinctions can accelerate evolution

© news.utexas.edu, Credit: Joel Lehman
At the start of the simulation, a biped robot controlled by a computationally evolved brain stands upright on a 16 meter by 16 meter surface. The simulation proceeds until the robot falls or until 15 seconds have elapsed.
A computer science team at The University of Texas at Austin has found that robots evolve more quickly and efficiently after a virtual mass extinction modeled after real-life disasters such as the one that killed off the dinosaurs. Beyond its implications for artificial intelligence, the research supports the idea that mass extinctions actually speed up evolution by unleashing new creativity in adaptations.

Computer scientists Risto Miikkulainen and Joel Lehman co-authored the study published today in the journal PLOS One, which describes how simulations of mass extinctions promote novel features and abilities in surviving lineages.

"Focused destruction can lead to surprising outcomes," said Miikkulainen, a professor of computer science at UT Austin. "Sometimes you have to develop something that seems objectively worse in order to develop the tools you need to get better."

In biology, mass extinctions are known for being highly destructive, erasing a lot of genetic material from the tree of life. But some evolutionary biologists hypothesize that extinction events actually accelerate evolution by promoting those lineages that are the most evolvable, meaning ones that can quickly create useful new features and abilities.


Comment: We are seeing many species exiting the planet at this juncture in the evolution of our planet. This research suggests that not all life will become extinct; that what remains may experience a comparable and parallel acceleration in evolution befitting its future on Earth. If this is the sixth extinction, there will undoubtedly be a seventh and...


Nebula

Supernovae found in 'wrong place at wrong time'

© NASA, ESA, and P. Jeffries and A. Feild (STScI)
This illustration offers a plausible scenario for how vagabond stars exploded as supernovae outside the cozy confines of galaxies. Panel 1: A pair of black holes comes together during a galaxy merger, dragging with them up to a million stars each. Panel 2: A double-star system wanders too close to the two black holes. Panel 3: The black holes then gravitationally catapult the stars out of the galaxy. At the same time, the stars are brought closer together. Panel 4: After getting booted out of the galaxy, the binary stars move even closer together as orbital energy is carried away from the duo in the form of gravitational waves. Panel 5: Eventually, the stars get close enough that one of them is ripped apart by tidal forces. Panel 6: As material from the dead star is quickly dumped onto the surviving star, a supernova occurs.
Several exploding stars have been found outside the cozy confines of galaxies, where most stars reside. These wayward supernovae are also weird because they exploded billions of years before their predicted detonations. Using archived observations from several telescopes, astronomers have developed a theory for where these doomed stars come from and how they arrived at their current homes. A new analysis of 13 supernovae -- including archived data from NASA's Hubble Space Telescope -- is helping astronomers explain how some young stars exploded sooner than expected, hurling them to a lonely place far from their host galaxies.

It's a complicated mystery of double-star systems, merging galaxies, and twin black holes that began in 2000 when the first such supernova was discovered, according to study leader Ryan Foley, University of Illinois at Urbana-Champaign. "This story has taken lots of twists and turns, and I was surprised every step of the way," he said. "We knew these stars had to be far from the source of their explosion as supernovae and wanted to find out how they arrived at their current homes."

Comment: When two black holes collide, it depends on the amount of hot gas surrounding each black hole. As they start to interact, this gas exerts a frictional force on the black holes, slowing down their spin rate. As the distance between them lessens, they begin emitting gravitational waves which continues to extract energy from the system. This causes them to continue coming together and eventually merge. The merger generates gravity waves detectable across space.


Blue Planet

Blue-green algae blooms increasingly threaten drinking water worldwide

© Oregon State University
Toxic Microcystis algae grow in a large bloom in the Copco Reservoir on the Klamath River, posing health risks to people, pets and wildlife.
A report concludes that blooms of toxic cyanobacteria, or blue-green algae, are a poorly monitored and underappreciated risk to recreational and drinking water quality in the United States, and may increasingly pose a global health threat.

Several factors are contributing to the concern. Temperatures and carbon dioxide levels have risen, many rivers have been dammed worldwide, and wastewater nutrients or agricultural fertilizers in various situations can cause problems in rivers, lakes and reservoirs.

No testing for cyanobacteria is mandated by state or federal drinking water regulators, according to scientists from Oregon State University, nor is reporting required of disease outbreaks associated with algal blooms. But changes in climate and land use, and even increasing toxicity of the bacteria themselves, may force greater attention to this issue in the future, the researchers said.