Scientists find iron 'snow' in Earth's core

Illustration of Earth's core.

The Earth's inner core is hot, under immense pressure and snow-capped, according to new research that could help scientists better understand forces that affect the entire planet.

The snow is made of tiny particles of iron -- much heavier than any snowflake on Earth's surface -- that fall from the molten outer core and pile on top of the inner core, creating piles up to 200 miles thick that cover the inner core.

The image may sound like an alien winter wonderland. But the scientists who led the research said it is akin to how rocks form inside volcanoes.

"The Earth's metallic core works like a magma chamber that we know better of in the crust," said Jung-Fu Lin, a professor in the Jackson School of Geosciences at The University of Texas at Austin and a co-author of the study.

The study is available online and will be published in the print edition of the journal JGR Solid Earth on December 23.

Youjun Zhang, an associate professor at Sichuan University in China, led the study. The other co-authors include Jackson School graduate student Peter Nelson; and Nick Dygert, an assistant professor at the University of Tennessee who conducted the research during a postdoctoral fellowship at the Jackson School.

The Earth's core can't be sampled, so scientists study it by recording and analyzing signals from seismic waves (a type of energy wave) as they pass through the Earth.

However, aberrations between recent seismic wave data and the values that would be expected based on the current model of the Earth's core have raised questions. The waves move more slowly than expected as they passed through the base of the outer core, and they move faster than expected when moving through the eastern hemisphere of the top inner core.

The study proposes the iron snow-capped core as an explanation for these aberrations. The scientist S.I. Braginkskii proposed in the early 1960s that a slurry layer exists between the inner and outer core, but prevailing knowledge about heat and pressure conditions in the core environment quashed that theory. However, new data from experiments on core-like materials conducted by Zhang and pulled from more recent scientific literature found that crystallization was possible and that about 15% of the lowermost outer core could be made of iron-based crystals that eventually fall down the liquid outer core and settle on top of the solid inner core.

"It's sort of a bizarre thing to think about," Dygert said. "You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers."

The researchers point to the accumulated snow pack as the cause of the seismic aberrations. The slurry-like composition slows the seismic waves. The variation in snow pile size -- thinner in the eastern hemisphere and thicker in the western -- explains the change in speed.

"The inner-core boundary is not a simple and smooth surface, which may affect the thermal conduction and the convections of the core," Zhang said.

The paper compares the snowing of iron particles with a process that happens inside magma chambers closer to the Earth's surface, which involves minerals crystalizing out of the melt and glomming together. In magma chambers, the compaction of the minerals creates what's known as "cumulate rock." In the Earth's core, the compaction of the iron contributes to the growth of the inner core and shrinking of the outer core.

And given the core's influence over phenomena that affects the entire planet, from generating its magnetic field to radiating the heat that drives the movement of tectonic plates, understanding more about its composition and behavior could help in understanding how these larger processes work.

Bruce Buffet, a geosciences professor at the University of California, Berkley who studies planet interiors and who was not involved in the study, said that the research confronts longstanding questions about the Earth's interior and could even help reveal more about how the Earth's core came to be.

"Relating the model predictions to the anomalous observations allows us to draw inferences about the possible compositions of the liquid core and maybe connect this information to the conditions that prevailed at the time the planet was formed," he said. "The starting condition is an important factor in Earth becoming the planet we know."

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Forgetfulness might depend on time of day

Pocket watch.

Can't remember something? Try waiting until later in the day. Researchers identified a gene in mice that seems to influence memory recall at different times of day and tracked how it causes mice to be more forgetful just before they normally wake up.

"We may have identified the first gene in mice specific to memory retrieval," said Professor Satoshi Kida from the University of Tokyo Department of Applied Biological Chemistry.

Every time you forget something, it could be because you didn't truly learn it -- like the name of the person you were just introduced to a minute ago; or it could be because you are not able to recall the information from where it is stored in your brain -- like the lyrics of your favorite song slipping your mind.

Many memory researchers study how new memories are made. The biology of forgetting is more complicated to study because of the difficulties of distinguishing between not knowing and not recalling.

"We designed a memory test that can differentiate between not learning versus knowing but not being able to remember," said Kida.

Researchers tested the memories of young adult male and female mice. In the "learning," or training, phase of the memory tests, researchers allowed mice to explore a new object for a few minutes.

Later, in the "recall" phase of the test, researchers observed how long the mice touched the object when it was reintroduced. Mice spend less time touching objects that they remember seeing previously. Researchers tested the mice's recall by reintroducing the same object at different times of day.

They did the same experiments with healthy mice and mice without BMAL1, a protein that regulates the expression of many other genes. BMAL1 normally fluctuates between low levels just before waking up and high levels before going to sleep.

Mice trained just before they normally woke up and tested just after they normally went to sleep did recognize the object.

Mice trained at the same time -- just before they normally woke up -- but tested 24 hours later did not recognize the object.

Healthy mice and mice without BMAL1 had the same pattern of results, but the mice without BMAL1 were even more forgetful just before they normally woke up. Researchers saw the same results when they tested mice on recognizing an object or recognizing another mouse.

Something about the time of day just before they normally wake up, when BMAL1 levels are normally low, causes mice to not recall something they definitely learned and know.

According to Kida, the memory research community has previously suspected that the body's internal, or circadian, clock that is responsible for regulating sleep-wake cycles also affects learning and memory formation.

"Now we have evidence that the circadian clocks are regulating memory recall," said Kida.

Researchers have traced the role of BMAL1 in memory retrieval to a specific area of the brain called the hippocampus. Additionally, researchers connected normal BMAL1 to activation of dopamine receptors and modification of other small signaling molecules in the brain.

"If we can identify ways to boost memory retrieval through this BMAL1 pathway, then we can think about applications to human diseases of memory deficit, like dementia and Alzheimer's disease," said Kida.

However, the purpose of having memory recall abilities that naturally fluctuate depending on the time of day remains a mystery.

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Mowing urban lawns less intensely increases biodiversity, saves money and reduces pests

The researchers combined data across North America and Europe using a meta-analysis, a way of aggregating results from multiple studies to increase statistical strength. They found strong evidence that increased mowing intensity of urban lawns -- which included parks, roundabouts and road verges -- had negative ecological effects, particularly on invertebrate and plant diversity. Pest species, on the other hand, benefitted from intense lawn management.

"Even a modest reduction in lawn mowing frequency can bring a host of environmental benefits: increased pollinators, increased plant diversity and reduced greenhouse gas emissions. At the same time, a longer, healthier lawn makes it more resistant to pests, weeds, and drought events." said Dr Chris Watson, lead author of the study.

The issue with regular lawn mowing is that it favours grasses, which grow from that base of the plant, and low growing species like dandelion and clover. Other species that have their growing tips or flowering stems regularly removed by mowing can't compete. Allowing plant diversity in urban lawns to increase has the knock-on effect of increasing the diversity of other organisms such as pollinators and herbivores.

The effect of intense lawn mowing on pest species was the least studied aspect of the research the authors looked at, featuring in seven datasets across three studies in Eastern Canada. However, in all of these studies they found that intensive lawn mowing resulted in an increase in the abundance of weeds and lawn pests.

"These findings support a lot of research done by the turfgrass industry that shows that the more disturbance a lawn gets, the higher the likelihood of pest and weed invasion." said Dr Chris Watson.

Common ragweed, which featured prominently in the studies, is one of the most allergenic plant species found in North America and Europe. Previous studies have estimated the cost of ragweed-based allergies to be CAD$155 million per year in Quebec and €133 million a year in Austria and Bavaria. Having a more rapid reproduction than other species, ragweed is able to colonise disturbances caused by intense mowing.

Chris Watson explained that "Certain lawn invaders, such as ragweed, can be decreased simply through reducing lawn mowing frequency. This will decrease the pollen load in the air and reduce the severity of hayfever symptoms, number of people affected, and medical costs."

To understand the economic costs of intensely mowed lawns the researchers used a case study of the city of Trois-Rivières, Quebec, Canada. By using data on mowing contractor costs they estimated a 36% reduction of public maintenance costs when mowing frequency was reduced from 15 to 10 times per year in high use lawn areas and 3 times to once a year in low use areas.

"If citizens would like to see urban greenspace improvement, they have the ability to influence how governments go about this -- especially if it does not cost more money!" said Dr Chris Watson. "Likewise, complaints about long, messy lawns could quickly reduce the appetite of local government to trial these approaches -- so it's important to have some community information and education as well. We need to shake the outdated social stigma that comes from having a lawn a few centimetres longer than your neighbour's"

The potential for long grass to harbour ticks and rodents is a common concern. However, Dr Chris Watson said there is little evidence to support this. "The presence of ticks are more strongly related to host populations, like deer, than type of vegetation. With respect to small mammals, some species prefer longer grass' whereas others do not. The next phase of our research aims to explore these negative perceptions in more detail."

For their meta-analysis the researchers identified studies in an urban setting that measured mowing intensity (either height or frequency) as an experimental factor. On top of the 14 studies they identified, which took place between 2004 and 2019, they also included three previously unpublished studies from their research group. A separate case study was used to estimate the economic costs of high intensity lawn management.

On the reasons for conducting a meta-analysis, Chris Watson explained that: "Often, ecological studies are done over only one or two years and can be heavily influenced by the weather conditions during the period of study. A meta-analysis looks beyond individual years or locations to provide a broad overview of a research subject."

The number of data sources from previous studies available to the authors ultimately limited the analysis. "In this case, all studies came from North America and Europe so there is a big opportunity in seeing if the trends we found are confirmed elsewhere. Likewise, all the studies were used to explore pest species were from Eastern Canada, so it is important to do more research in other places before applying these results generally." said Dr Chris Watson.

When looking at the economic impacts of intense lawn management the authors were only able to incorporate contractor costs which included worker's salaries, equipment operation and fuel. They were unable to include the costs of pesticides and fertiliser or factor in indirect economic benefits from improved ecosystem services like pollination.

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Why is drinking in moderation so difficult for some people?

Compulsive drinking may be due to dysfunction in a specific brain pathway that normally helps keep drinking in check. The results are reported in the journal Biological Psychiatry.

In the United States, 14 million adults struggle with alcohol use disorder (AUD) -- formerly known as alcoholism. This disorder makes individuals unable to stop drinking even when they know the potential risks to health, jobs, and relationships.

"Difficulty saying no to alcohol, even when it could clearly lead to harm, is a defining feature of alcohol use disorders," said Andrew Holmes, PhD, senior investigator of the study and Chief of the Laboratory on Behavioral and Genomic Neuroscience at the National Institute on Alcohol Abuse and Alcoholism (NIAAA). "This study takes us a step further in understanding the brain mechanisms underlying compulsive drinking."

Many complex parts of behavior -- emotion, reward, motivation, anxiety -- are regulated by the cortex, the outer layers of the brain that are responsible for complex processes like decision-making. Unlike drugs like cocaine, alcohol has broad effects on the brain, which makes narrowing down a target for therapeutic treatment much more difficult.

"We want to understand how the brain normally regulates drinking, so we can answer questions about what happens when this regulation isn't happening as it should," said Lindsay Halladay, PhD, Assistant Professor of Psychology and Neuroscience at Santa Clara University, and lead author of the study.

To study how the brain regulates drinking, Halladay and colleagues trained mice in the lab to press a lever for an alcohol reward. Once trained, the mice were presented with a new, conflicting situation: press the same lever for alcohol and receive a light electric shock to their feet, or avoid that risk but forfeit the alcohol. After a short session, most mice quickly learn to avoid the shock and choose to give up the alcohol.

Halladay's team first used surgically-implanted electrodes to measure activity in regions of the cortex during that decision.

"We found a group of neurons in the medial prefrontal cortex that became active when mice approached the lever but aborted the lever press," said Halladay. "These neurons only responded when the mice did not press the lever, apparently deciding the risk of shock was too great, but not when mice chose alcohol over the risk of shock. This means that the neurons we identified may be responsible for putting the brakes on drinking when doing so may be dangerous."

The medial prefrontal cortex (mPFC) plays a role in many forms of decision-making and communicates with many regions of the brain, so Halladay's team explored those external connections.

The team used optogenetics, a viral engineering technique that allowed them to effectively shut down precise brain pathways by shining light in the brain. They shut down activity of cells in the mPFC that communicate with the nucleus accumbens, an area of the brain important for reward, and found that the number of risky lever presses increased.

"Shutting down this circuit restored alcohol-seeking despite the risk of shock," said Halladay. "This raises the possibility that alcohol use disorder stems from some form of dysfunction in this pathway."

Understanding compulsive drinking in some people relies on identifying the neural pathway that keeps drinking in check.

"Current treatments just aren't effective enough," said Halladay. "Nearly half of all people treated for AUD relapse within a year of seeking treatment."

Read more at Science Daily

NASA maps inner Milky Way, sees cosmic 'candy cane'

This image of the inner galaxy color codes different types of emission sources by merging microwave data (green) mapped by the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) instrument with infrared (850 micrometers, blue) and radio observations (19.5 centimeters, red). Where star formation is in its infancy, cold dust shows blue and cyan, such as in the Sagittarius B2 molecular cloud complex. Yellow reveals more well-developed star factories, as in the Sagittarius B1 cloud. Red and orange show where high-energy electrons interact with magnetic fields, such as in the Radio Arc and Sagittarius A features. An area called the Sickle may supply the particles responsible for setting the Radio Arc aglow. Within the bright source Sagittarius A lies the Milky Way's monster black hole. The image spans a distance of 750 light-years.

A feature resembling a candy cane appears at the center of this colorful composite image of our Milky Way galaxy's central zone. But this is no cosmic confection. It spans 190 light-years and is one of a set of long, thin strands of ionized gas called filaments that emit radio waves.

This image includes newly published observations using an instrument designed and built at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Called the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO), the instrument was used in concert with a 30-meter radio telescope located on Pico Veleta, Spain, operated by the Institute for Radio Astronomy in the Millimeter Range headquartered in Grenoble, France.

"GISMO observes microwaves with a wavelength of 2 millimeters, allowing us to explore the galaxy in the transition zone between infrared light and longer radio wavelengths," said Johannes Staguhn, an astronomer at Johns Hopkins University in Baltimore who leads the GISMO team at Goddard. "Each of these portions of the spectrum is dominated by different types of emission, and GISMO shows us how they link together."

GISMO detected the most prominent radio filament in the galactic center, known as the Radio Arc, which forms the straight part of the cosmic candy cane. This is the shortest wavelength at which these curious structures have been observed. Scientists say the filaments delineate the edges of a large bubble produced by some energetic event at the galactic center, located within the bright region known as Sagittarius A about 27,000 light-years away from us. Additional red arcs in the image reveal other filaments.

"It was a real surprise to see the Radio Arc in the GISMO data," said Richard Arendt, a team member at the University of Maryland, Baltimore County and Goddard. "Its emission comes from high-speed electrons spiraling in a magnetic field, a process called synchrotron emission. Another feature GISMO sees, called the Sickle, is associated with star formation and may be the source of these high-speed electrons."

Two papers describing the composite image, one led by Arendt and one led by Staguhn, were published on Nov. 1 in the Astrophysical Journal.

The image shows the inner part of our galaxy, which hosts the largest and densest collection of giant molecular clouds in the Milky Way. These vast, cool clouds contain enough dense gas and dust to form tens of millions of stars like the Sun. The view spans a part of the sky about 1.6 degrees across -- equivalent to roughly three times the apparent size of the Moon -- or about 750 light-years wide.

To make the image, the team acquired GISMO data, shown in green, in April and November 2012. They then used archival observations from the European Space Agency's Herschel satellite to model the far-infrared glow of cold dust, which they then subtracted from the GISMO data. Next, they added, in blue, existing 850-micrometer infrared data from the SCUBA-2 instrument on the James Clerk Maxwell Telescope near the summit of Maunakea, Hawaii. Finally, they added, in red, archival longer-wavelength 19.5-centimeter radio observations from the National Science Foundation's Karl G. Jansky Very Large Array, located near Socorro, New Mexico. The higher-resolution infrared and radio data were then processed to match the lower-resolution GISMO observations.

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ESO observations reveal black holes' breakfast at the cosmic dawn

This image shows one of the gas halos newly observed with the MUSE instrument on ESO's Very Large Telescope superimposed to an older image of a galaxy merger obtained with ALMA. The large-scale halo of hydrogen gas is shown in blue, while the ALMA data is shown in orange.

Astronomers using ESO's Very Large Telescope have observed reservoirs of cool gas around some of the earliest galaxies in the Universe. These gas halos are the perfect food for supermassive black holes at the centre of these galaxies, which are now seen as they were over 12.5 billion years ago. This food storage might explain how these cosmic monsters grew so fast during a period in the Universe's history known as the Cosmic Dawn.

"We are now able to demonstrate, for the first time, that primordial galaxies do have enough food in their environments to sustain both the growth of supermassive black holes and vigorous star formation," says Emanuele Paolo Farina, of the Max Planck Institute for Astronomy in Heidelberg, Germany, who led the research published today in The Astrophysical Journal. "This adds a fundamental piece to the puzzle that astronomers are building to picture how cosmic structures formed more than 12 billion years ago."

Astronomers have wondered how supermassive black holes were able to grow so large so early on in the history of the Universe. "The presence of these early monsters, with masses several billion times the mass of our Sun, is a big mystery," says Farina, who is also affiliated with the Max Planck Institute for Astrophysics in Garching bei München. It means that the first black holes, which might have formed from the collapse of the first stars, must have grown very fast. But, until now, astronomers had not spotted 'black hole food' -- gas and dust -- in large enough quantities to explain this rapid growth.

To complicate matters further, previous observations with ALMA, the Atacama Large Millimeter/submillimeter Array, revealed a lot of dust and gas in these early galaxies that fuelled rapid star formation. These ALMA observations suggested that there could be little left over to feed a black hole.

To solve this mystery, Farina and his colleagues used the MUSE instrument on ESO's Very Large Telescope in the Chilean Atacama Desert to study quasars -- extremely bright objects powered by supermassive black holes which lie at the centre of massive galaxies. The study surveyed 31 quasars that are seen as they were more than 12.5 billion years ago, at a time when the Universe was still an infant, only about 870 million years old. This is one of the largest samples of quasars from this early on in the history of the Universe to be surveyed.

The astronomers found that 12 quasars were surrounded by enormous gas reservoirs: halos of cool, dense hydrogen gas extending 100,000 light years from the central black holes and with billions of times the mass of the Sun. The team, from Germany, the US, Italy and Chile, also found that these gas halos were tightly bound to the galaxies, providing the perfect food source to sustain both the growth of supermassive black holes and vigorous star formation.

The research was possible thanks to the superb sensitivity of MUSE, the Multi Unit Spectroscopic Explorer, on ESO's VLT, which Farina says was "a game changer" in the study of quasars. "In a matter of a few hours per target, we were able to delve into the surroundings of the most massive and voracious black holes present in the young Universe," he adds. While quasars are bright, the gas reservoirs around them are much harder to observe. But MUSE could detect the faint glow of the hydrogen gas in the halos, allowing astronomers to finally reveal the food stashes that power supermassive black holes in the early Universe.

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Changes in the immune system explain why belly fat is bad for thinking

Iowa State researchers have found for the first time that less muscle and more body fat may affect how flexible our thinking gets as we become older, and changes in parts of the immune system could be responsible.

These findings could lead to new treatments that help maintain mental flexibility in aging adults with obesity, sedentary lifestyles, or muscle loss that naturally happens with aging.

The study, led by Auriel Willette, assistant professor of food science and human nutrition, and Brandon Klinedinst, a PhD student in neuroscience, looked at data from more than 4,000 middle-aged to older UK Biobank participants, both men and women. The researchers examined direct measurements of lean muscle mass, abdominal fat, and subcutaneous fat, and how they were related to changes in fluid intelligence over six years.

Willette and Klinedinst discovered people mostly in their 40s and 50s who had higher amounts of fat in their mid-section had worse fluid intelligence as they got older. Greater muscle mass, by contrast, appeared to be a protective factor. These relationships stayed the same even after taking into account chronological age, level of education, and socioeconomic status.

"Chronological age doesn't seem to be a factor in fluid intelligence decreasing over time," Willette said. "It appears to be biological age, which here is the amount of fat and muscle."

Generally, people begin to gain fat and lose lean muscle once they hit middle age, a trend that continues as they get older. To overcome this, implementing exercise routines to maintain lean muscle becomes more important. Klinedinst said exercising, especially resistance training, is essential for middle-aged women, who naturally tend to have less muscle mass than men.

The study also looked at whether or not changes in immune system activity could explain links between fat or muscle and fluid intelligence. Previous studies have shown that people with a higher body mass index (BMI) have more immune system activity in their blood, which activates the immune system in the brain and causes problems with cognition. BMI only takes into account total body mass, so it has not been clear whether fat, muscle, or both jump-start the immune system.

In this study, in women, the entire link between more abdominal fat and worse fluid intelligence was explained by changes in two types of white blood cells: lymphocytes and eosinophils. In men, a completely different type of white blood cell, basophils, explained roughly half of the fat and fluid intelligence link. While muscle mass was protective, the immune system did not seem to play a role.

While the study found correlations between body fat and decreased fluid intelligence, it is unknown at this time if it could increase the risk of Alzheimer's disease.

"Further studies would be needed to see if people with less muscle mass and more fat mass are more likely to develop Alzheimer's disease, and what the role of the immune system is," Klinedinst said.

Starting a New Year's resolution now to work out more and eat healthier may be a good idea, not only for your overall health, but to maintain healthy brain function.

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The majority consider themselves more environmentally friendly than others

Research from the University of Gothenburg shows that we tend to overestimate our personal environmental engagement. In a study with participants from Sweden, the United States, England, and India, most participants were convinced that they acted more environmentally friendly than the average person.

In the study, over 4,000 people responded to how much, and how often, they perform environmentally friendly activities compared to others. For example, buying eco-labelled products, saving household energy, and reducing purchases of plastic bags.

It turned out that the majority of the participants rated themselves as more environmentally friendly than others. Both in comparison to unknown people, and to their friends.

"The results point out our tendency to overestimate our own abilities, which is in line with previous studies where most people consider themselves to be more honest, more creative, and better drivers than others. This study shows that over-optimism, or the "better-than-average" effect, also applies to environmentally friendly behaviours," says environmental psychology researcher Magnus Bergquist.

After analyzing data from different types of environmentally friendly activities, results revealed that the participants were more likely to overestimate their engagement in activities they perform often. Many seemed to draw the faulty conclusion that the activities they perform often, they also perform more often than others.

A consequence of thinking that you are more environmentally friendly than others, is that it can reduce the motivation to act environmentally friendly in the future. The study also showed that when we think we are more environmentally friendly than others, we actually tend to become somewhat less environmentally friendly.

According to Magnus Bergquist, one way of reducing the risk of over-optimism standing in our way for a real environmental commitment, may be trying to have a more realistic view of our own environmental efforts.

"If you think about it logically, the majority cannot be more environmentally friendly than others. One way to change this faulty opinion, is to inform people that others actually behave environmentally friendly, and thereby creating an environmentally friendly norm. Social norms affect us also in this area, we know this from previous studies," says Magnus Bergquist.

From Science Daily

Bilingual children are strong, creative storytellers, study shows

Bilingual children use as many words as monolingual children when telling a story, and demonstrate high levels of cognitive flexibility, according to new research by University of Alberta scientists.

"We found that the number of words that bilingual children use in their stories is highly correlated with their cognitive flexibility -- the ability to switch between thinking about different concepts," said Elena Nicoladis, lead author and professor in the Department of Psychology in the Faculty of Science. "This suggests that bilinguals are adept at using the medium of storytelling."

Vocabulary is a strong predictor of school achievement, and so is storytelling. "These results suggest that parents of bilingual children do not need to be concerned about long-term school achievement, said Nicoladis. "In a storytelling context, bilingual kids are able to use this flexibility to convey stories in creative ways."

The research examined a group of French-English bilingual children who have been taught two languages since birth, rather than learning a second language later in life. Results show that bilingual children used just as many words to tell a story in English as monolingual children. Participants also used just as many words in French as they did in English when telling a story.

Previous research has shown that bilingual children score lower than monolingual children on traditional vocabulary tests, meaning this results are changing our understanding of multiple languages and cognition in children.

"The past research is not surprising," added Nicoladis. "Learning a word is related to how much time you spend in each language. For bilingual children, time is split between languages. So, unsurprisingly, they tend to have lower vocabularies in each of their languages. However, this research shows that as a function of storytelling, bilingual children are equally strong as monolingual children."

This research used a new, highly sensitive measure for examining cognitive flexibility, examining a participant's ability to switch between games with different rules, while maintaining accuracy and reaction time. This study builds on previous research examining vocabulary in bilingual children who have learned English as a second language.

From Science Daily

Your DNA is not your destiny -- or a good predictor of your health

In most cases, your genes have less than five per cent to do with your risk of developing a particular disease, according to new research by University of Alberta scientists.

In the largest meta-analysis ever conducted, scientists have examined two decades of data from studies that examine the relationships between common gene mutations, also known as single nucleotide polymorphisms (SNPs), and different diseases and conditions. And the results show that the links between most human diseases and genetics are shaky at best.

"Simply put, DNA is not your destiny, and SNPs are duds for disease prediction," said David Wishart, professor in the University of Alberta's Department of Biological Sciences and the Department of Computing Science and co-author on the study. "The vast majority of diseases, including many cancers, diabetes, and Alzheimer's disease, have a genetic contribution of 5 to 10 per cent at best."

The study also highlights some notable exceptions, including Crohn's disease, celiac disease, and macular degeneration, which have a genetic contribution of approximately 40 to 50 per cent.

"Despite these rare exceptions, it is becoming increasingly clear that the risks for getting most diseases arise from your metabolism, your environment, your lifestyle, or your exposure to various kinds of nutrients, chemicals, bacteria, or viruses," explained Wishart.

Wishart and his research collaborators suggest that measuring metabolites, chemicals, proteins, or the microbiome provides a much more accurate measure of human disease risk and are also more accurate for diagnosis. The findings fly in the face of many modern gene testing businesses models, which suggest that gene testing can accurately predict someone's risk for disease.

"The bottom line is that if you want to have an accurate measure of your health, your propensity for disease or what you can do about it, it's better to measure your metabolites, your microbes or your proteins -- not your genes," added Wishart. "This research also highlights the need to understand our environment and the safety or quality of our food, air, and water."

From Science Daily