New Dating System Could Reveal Secrets of Earth’s Ancient Climate

Posted April 21st, 2014 at 7:51 pm (UTC+0)
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Ice sample trench at Antarctica's Taylor Glacier. Ice core samples from this site were analyzed with the Atom Trace Analysis technique at Argonne National Laboratory, Chicago. (Hinrich Schaefer/Oregon State University)

Ice sample trench at Antarctica’s Taylor Glacier. Ice core samples from this site were analyzed with the Atom Trace Analysis technique at Argonne National Laboratory, Chicago. (Hinrich Schaefer/Oregon State University)

Scientists have a new tool in the quest to learn more about Earth’s ancient climate, including the mechanisms that plunged our planet into and out of ice ages.

The new tool is a scientific technique called radiometric krypton dating, which recently allowed researchers to accurately determine the age of a 120,000-year-old Antarctic ice core sample.

Details of this finding were published by the Proceedings of the National Academies of Science (PNAS).

One of the most important steps for scientists investigating past climatic events is the ability to find polar ice samples that date back as far into time as possible. These ice samples contain frozen bubbles of ancient air that can be analyzed in a laboratory, allowing scientists to reconstruct Earth’s climate history.

“The oldest ice found in drilled cores is around 800,000 years old and with this new technique we think we can look in other regions and successfully date polar ice back as far as 1.5 million years,” said Oregon State University’s Christo Buizert, lead author of the PNAS paper. “That is very exciting because a lot of interesting things happened with the Earth’s climate prior to 800,000 years ago that we currently cannot study in the ice core record.”

Like the well-known carbon-14 dating system used to determine the age of organic materials such as wood, Krypton dating also measures the decay of a radioactive isotope which is known to have a constant and well-known decay rate, and compares it to a stable isotope – an isotope that doesn’t automatically undergo radioactive decay.

However, unlike carbon-14 dating, which was developed in the late 1940s, krypton is a noble gas that is stable, doesn’t interact chemically, and has a half-life of around 230,000 years. Scientists have found that the carbon dating system doesn’t work well on ice samples because the carbon-14 isotope is produced within the ice itself by cosmic rays and is only able to date material to about 50,000 years ago.

Ice core driller Tanner Kuhl with the blue ice drill on Taylor Glacier in Antarctica. The field camp is visible in the background. (© Xavier Fain/Oregon State University)

Ice core driller Tanner Kuhl with the blue ice drill on Taylor Glacier in Antarctica. The field camp is visible in the background. (© Xavier Fain/Oregon State University)

According to the researchers, Krypton is  also produced by cosmic rays that bombard the Earth but is then stored within air bubbles that are trapped inside Antarctic ice. Krypton produces two isotopes that help scientists perform the dating process: one is a radioactive isotope called krypton-81, which has a very slow decay time, and the other is krypton-83, which is a stable isotope that does not decay.  Scientists are able to determine the age of the ice by comparing the percentage of stable isotopes (krypton-83) to the radioactive isotopes (krypton-81).

The researchers said that the radio-krypton dating technique has be around for more than 40 years, but it wasn’t until 2011 when scientists at the Argonne National Laboratory in Chicago developed an innovative method, named the Atom Trap Trace Analysis (ATTA), that radiometric krypton dating of water and ice became possible.

For their ice core dating experiment, researchers melted several 300-kilogram lumps of ice that were retrieved from the Taylor Glacier in Antarctica, in order to release the air stored in the bubbles. The air from the ice bubbles was sent to scientists at the University of Bern, Switzerland, who isolated krypton from the air samples. The krypton was then sent to the Argonne National Laboratory for an Atom Trap Trace Analysis, which revealed that the glacier samples to be 120,000 years old.

With this technique to help them with their work, researchers say their new challenge is to find some of the oldest ice in Antarctica, something that isn’t as easy as it may sound.

Scientists use a pulley system to load 25-kilogram ice cores into the melter setup. Scientists used the melter to extract air from bubbles formed in the ice.  The air samples were sent to a lab for analysis which indicated the samples to be 120,000 years old. (© Vasilii Petrenko/Oregon State University)

Scientists use a pulley system to load 25-kilogram ice cores into the melter setup. (© Vasilii Petrenko/Oregon State University)

“Most people assume that it’s a question of just drilling deeper for ice cores, but it’s not that simple,” said Edward Brook, an Oregon State University geologist and co-author on the study. “Very old ice probably exists in small isolated patches at the base of the ice sheet that have not yet been identified, but in many places it has probably melted and flowed out into the ocean.”

According to Buizert, it’s important that Earth’s climate be reconstructed as far back as 1.5 million years because it will help scientists learn more about a change in the number of ice ages that took place in what is called the Middle Pleistocene transition.  While scientists think Earth has shifted in and out of ice ages every 100,000 years for the past 800,000 years, evidence suggests the planet entered and exited from ice ages much more frequently before that time – at every 40,000 years.

“Why was there a transition from a 40,000-year cycle to a 100,000-year cycle?” Buizert said. “Some people believe a change in the level of atmospheric carbon dioxide may have played a role. That is one reason we are so anxious to find ice that will take us back further in time so we can further extend data on past carbon dioxide levels and test this hypothesis.”

NASA Lunar Explorer Has Smashing End

Posted April 18th, 2014 at 4:52 pm (UTC+0)
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Artist's concept of LADEE passing over the lunar surface (NASA)

Artist’s concept of LADEE passing over the lunar surface (NASA)

NASA’s Lunar Atmosphere and Dust Environment Explorer, or LADEE mission had a smashing ending early Friday morning when the US space agency crashed the spacecraft into the moon’s surface.

The ground controllers, monitoring the spacecraft’s operations from NASA’s Ames Research Center in Moffett Field, California, confirmed that it impacted the lunar surface as planned sometime between 2130 and 2222 UTC on Friday (4/18/14).

One of the final images taken by LADEE as it orbits the moon shows a minor lunar mountain range, Montes Agricola and the flat-floored crater Raman. (NASA Ames)

One of the final images taken by LADEE, as it orbits the moon, shows a minor lunar mountain range, Montes Agricola and the flat-floored crater Raman. (NASA Ames)

Mission officials said that LADEE didn’t have enough fuel to remain in an ongoing lunar orbit or sustain its science operations.  And, since the spacecraft’s orbit was already naturally decaying following the mission’s final science phase earlier this month, it was decided that it would be intentionally sent down onto the lunar surface.

Flying at less than 2 kilometers above the lunar surface, LADEE mission specialists said that the final science phase allowed them to gather some very unique measurements.

NASA said that as it impacted the moon, the vending machine-sized LADEE spacecraft heated up several hundred degrees and broke apart or vaporized.  The space agency believes that if any material remained after crashing, it’s likely buried in the moon’s shallow craters.

“At the time of impact, LADEE was traveling at a speed of 3,600 miles per hour – about three times the speed of a high-powered rifle bullet,” said Rick Elphic, LADEE project scientist at Ames. “There’s nothing gentle about impact at these speeds – it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area. It will be interesting to see what kind of feature LADEE has created.”

A Minotaur V rocket carrying the Lunar Atmosphere and Dust Environment Explorer lifts off from NASA's Wallops Flight Facility in Virginia on Friday, Sept. 6, 2013. (NASA/Chris Perry)

A Minotaur V rocket carrying the Lunar Atmosphere and Dust Environment Explorer lifts off from NASA’s Wallops Flight Facility in Virginia on Friday, Sept. 6, 2013. (NASA/Chris Perry)

LADEE was launched from NASA’s Wallops Flight Facility in Virginia on September 7, 2013 from NASA’s Wallops Flight Facility in Virginia.  The spacecraft entered lunar orbit on October 6, 2013 and started to gather data on November 10, 2013. In January NASA decided to extend the LADEE mission by an extra month after it finished its very successful primary science phase which took place earlier this month (April 2014).

Throughout its mission LADEE was able to collect some very comprehensive information about the lunar atmosphere’s structure and composition.

NASA scientists continue to pore through the data gathered throughout the lunar spacecraft’s mission and are hoping that it will provide an answer to a question that has puzzled many since the Apollo moon missions of the late 1960’s early 1970’s. Was the pre-sunrise glow that was observed just above the moon’s horizon caused by lunar dust that had been electrically charged by sunlight?

Thousands of people from around the world shared in the final part of LADEE’s mission by taking part in a NASA sponsored internet contest called “Take the Plunge”.  The contest challenged participants to guess the date and time the spacecraft would crash into the moon. Those who provided correct answers will win a digital congratulatory certificate.

“LADEE was a mission of firsts, achieving yet another first by successfully flying more than 100 orbits at extremely low altitudes,” said Joan Salute, LADEE program executive, at NASA Headquarters in Washington. “Although a risky decision, we’re already seeing evidence that the risk was worth taking.”

Video conception of LADEE’S final moments (NASA/Ames)

Study: Air Pollution Over Asia Found to Impact Global Weather

Posted April 16th, 2014 at 8:01 pm (UTC+0)
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Cars drive on the Three Ring Road amid the heavy haze in Beijing February 26, 2014. China's north is suffering a pollution crisis, with the capital Beijing itself shrouded in acrid smog. Authorities have introduced anti-pollutionpolicies and often pledged to clean up the environment but the problem has not eased. (REUTERS/Jason Lee)

Cars drive on the Three Ring Road amid the heavy haze in Beijing February 26, 2014. (REUTERS/Jason Lee)

Researchers from Texas, California and Washington recently compared air pollution data provided by the Intergovernmental Panel on Climate Change for the years 1850 through 2000 and found that human-made atmospheric particulates (aerosols) from Asia are having an impact on the Pacific storm track, which is a critical driver of global atmospheric circulation that influences weather over most of the world.

The researchers took this historical data and fed it into an advanced global climate model (GCM), a computer model of the general circulation of Earth’s atmosphere, to produce two climate scenarios. One of these scenarios reflected conditions of 1850, considered to be a time period before the industrial era.  The other represented the conditions of 2000, or present time.

Writing in a recent edition of the Proceedings of the National Academy of Sciences (PNAS), the researchers from Texas A&M University, the Pacific Northwest National Laboratory in Richland Washington, the University of California at San Diego and NASA’s Jet Propulsion Laboratory compared the results of the two scenarios and found that human-made aerosols (particulates) overwhelmingly impact cloud formations and mid-latitude cyclones, also called extra tropical cyclones, that are usually associated with the Pacific storm track.

The Pacific storm track transports heat and moisture along its path and the researchers said that they have found an increase in the transfer of heat and moisture that appears further along the storm track, which they said means that the Pacific storm track is intensified because of the discharge of Asian air pollution.

Recent research has shown that atmospheric aerosols affect the world’s climate by dispersing or absorbing the sun’s radiation and by changing the formation of clouds.

Scientists have expressed concern about the rising levels of these particulates in the atmosphere because of the possible effects they could have on regional to worldwide atmospheric circulation.

“There appears to be little doubt that these particles from Asia affect storms sweeping across the Pacific and subsequently the weather patterns in North America and the rest of the world,” said Renyi Zhang from Texas A&M’s Department of Atmospheric Sciences, one of the study’s authors.

Animation of activity along the Pacific storm track (Geophysical Fluid Dynamics Laboratory/NOAA)

Simulation of activity along the Pacific storm track (Geophysical Fluid Dynamics Laboratory/NOAA)

Zhang said that the results in the two scenarios produced by the climate model used by his team clearly indicate that aerosols made by human activities from “fast-growing Asian economies” not only impact the formation of storms but also global air circulation along the Pacific storm track.

The researchers also found that the increased pollution from Asia tends to make storms over the Pacific deeper, stronger and more intense, producing more precipitation.

“Our results support previous findings that show that particles in the air over Asia tend to affect global weather patterns,” Zhang said.  “It shows they can affect the Earth’s weather significantly.”

Scientist 99% Sure Global Climate Change is Man-Made

Posted April 14th, 2014 at 7:16 pm (UTC+0)
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A Canadian physicist says his studies have all but completely ruled out the premise that global warming throughout the industrial era has not been merely a natural fluctuation in Earth’s climate, as some have been claiming.  The assertion was made after the scientist analyzed temperature data from as far back as 1500.

McGill University study says that there's a 99% chance that global climate change is man-made (otodo via Flickr/Creative Commons)

McGill University study says that there’s a 99% chance that global climate change is man-made (otodo via Flickr/Creative Commons)

“This study will be a blow to any remaining climate-change deniers,” said study author Shaun Lovejoy who is also a professor of physics at McGill University in Montreal. “Their two most convincing arguments – that the warming is natural in origin, and that the computer models are wrong – are either directly contradicted by this analysis, or simply do not apply to it.”

Published in a recent edition of the journal Climate Dynamics, the study, based on statistical analysis of historical data rather on complex computer models used in previous studies, provides a new perspective to the question of what is behind global warming trends.

Lovejoy said that his analysis led him to conclude “with confidence levels great than 99%, and most likely greater than 99.9%,” that global warming since 1880 has been mostly caused by man-made emissions from the burning of fossil fuels and long-term temperature variations not caused by nature.

The historical temperature data Lovejoy used for times prior to the industrial era (before 1760) were estimates that were made from “multi-proxy climate reconstructions” that had been developed by scientists in recent years.

The climate reconstructions took into consideration a variety of natural indicators such as information from tree rings, ice cores, and lake sediments.

For his data from the industrial era, Lovejoy used levels of carbon-dioxide produced by the burning of fossil fuels as a representation for all human caused climate changes, since there has been a close relationship between the world’s economic activity and the release of greenhouse gases and particulate pollution.

“This allows the new approach to implicitly include the cooling effects of particulate pollution that are still poorly quantified in computer models,” said Lovejoy.

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

Lovejoy said that his findings complement those made in a report just released by the UN’s IPCC.  He said that his study predicted, with 95% confidence, that doubling the carbon-dioxide levels in the atmosphere would increase global temperatures between 1.9 and 4.2 degrees Celsius.  The IPCC’s prediction puts the rise in temperature between 1.5 to 4.5 degrees Celsius if atmospheric carbon-dioxide levels double.

“We’ve had a fluctuation in average temperature that’s just huge since 1880 – on the order of about 0.9 degrees Celsius,” said Lovejoy. “This study shows that the odds of that being caused by natural fluctuations are less than one in a hundred and are likely to be less than one in a thousand.”

Astronomers May Have Spotted A Moon Orbiting an Extrasolar Planet

Posted April 11th, 2014 at 7:32 pm (UTC+0)
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An international team may have discovered the first exomoon orbiting a planet in a distant solar system such as what's illustrated here in this artist rendition. (NASA/JPL/Cal-Tech)

An international team may have discovered the very first exomoon orbiting a planet in a distant solar system such as what’s illustrated here in this artist rendition. (NASA/JPL/Cal-Tech)

According to NASA, more than 1,000 extrasolar planets have been confirmed in recent years. There are also thousands more potential planets beyond our solar system that are waiting to be discovered.

Now, an international group of astronomers think they may have found the first exomoon, or moon circling an exoplanet, some 1,800 light years away from Earth.  This possible planet/moon system has been dubbed MOA-2011-BLG-262.

Then again, what the astronomers saw just might be some other kind of object, since they said it’s impossible to confirm its presence.  Nonetheless the scientists call their finding a “tantalizing first step” in the search for other exomoons.

The researchers said that they made their discovery by watching a chance encounter of objects in our galaxy, something that can only be observed once.

“We won’t have a chance to observe the exomoon candidate again,” said David Bennett of the University Of Notre Dame, lead author of a new paper published in the Astrophysical Journal that outlines the discovery. “But we can expect more unexpected finds like this,” he adds.

The research was led by a scientific consortium called the Japan-New Zealand-American Microlensing Observations in Astrophysics (MOA) and the Probing Lensing Anomalies NETwork (PLANET) programs.

Using telescopes located in New Zealand and Tasmania, the research team took advantage of an astronomical phenomenon that’s known as gravitational microlensing.

For example, whenever a nearby star passes directly between Earth and a more distant star, the gravitational field of the closer star will bend and focus the light of that distant star much like a lens in an optical telescope.

...or could the discovery be that of a distant solar system, containing an exoplanet, with a mass about 18 times that of Earth, orbiting a small, dim star  such as what's illustrated here in this artist rendering (NASA/JPL-Caltech)

…or could the discovery be that of a distant solar system, containing an exoplanet having a mass about 18 times that of Earth, orbiting a small, dim star such as what’s illustrated here in this artist rendering (NASA/JPL-Caltech)

If the star closest to Earth should happen to have a planet orbiting it, the scientists said that the planet would serve as a secondary lens that would further brighten or dim the distant object’s light even more.

Through careful analysis of these brightening/dimming events, the astronomers then can determine the mass of the closer star relative to its orbiting planet.

But the astronomers point out that sometimes the object closest to earth may not be a star, but a free-floating planet with a moon circling it. In this case researchers might then be able to measure the mass of the planet relative to its orbiting moon.

While they haven’t been successful so far, astronomers have been trying to locate exomoons orbiting distant planets by using other means, such as data provided by NASA’s Kepler mission.

For the research that led to this new discovery, the nature of the objects that were closest to Earth weren’t really clear to the astronomers.

They said that the ratio of the larger object to its smaller companion is 2,000 to 1 which could mean that the two objects could either be a small, dim star that’s orbited by a planet about 18 times the mass of Earth, or the pair could be a planet that is more massive than Jupiter circled by a moon with a mass that’s less than Earth.

The research team said that they have no way of telling which of the two circumstances is correct.

“One possibility is for the lensing system to be a planet and its moon, which if true, would be a spectacular discovery of a totally new type of system,” said Wes Traub, chief scientist for NASA’s Exoplanet Exploration Program office at the Jet Propulsion Laboratory in Pasadena, California.  Traub, who wasn’t involved with the international team’s studies, also said that “The researchers’ models point to the moon solution, but if you simply look at what scenario is more likely in nature, the star solution wins.”

The astronomers said to get a true answer in determining whether or not they observed an exomoon and not another star system they would need to figure out the actual distance to the circling twosome.

The Microlensing Observations in Astrophysics (MOA) telescope dome located atop Mount John on New Zealand's South Island (Aidan/ASGW via Flickr/Creative Commons)

The Microlensing Observations in Astrophysics (MOA) telescope dome located atop Mount John on New Zealand’s South Island (Aidan/ASGW via Flickr/Creative Commons)

A pair of objects closer to Earth that are low in mass, according to the astronomers, will produce the same kind of brightening event as one that would be produced by two more massive objects located farther away. But unfortunately once the observed brightening/dimming event is over; it’s very difficult for the scientists to take the needed additional measurements to calculate the distance.  That means the actual identity of what may or may not be an exomoon will remain a mystery.

The astronomers said that perhaps sometime in the future, it just may be possible to acquire these distance measurements during lensing events by using, for example, NASA’s Spitzer and Kepler space telescopes.

If it turns out that this sighting is actually a real exomoon that’s orbiting a free-floating planet, the astronomers think that the planet may have been kicked out of a young planetary system, bringing its orbiting moon along for the ride as a travel companion.

Researchers Discover How to Speed Metabolism

Posted April 9th, 2014 at 6:42 pm (UTC+0)
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obese-mainHave you ever wondered why some people can eat and eat but never gain weight while others easily put on pounds?

Scientists say that the body’s natural ability to control weight is tied to the body’s natural rate of burning energy, something called basal cellular metabolism. One of the reasons some people can eat without gaining weight is because they have higher metabolism rates.

A research team at Beth Israel Deaconess Medical Center in Boston has discovered that altering the biochemical process that underlies a cell’s ability to burn energy could help speed a person’s metabolism possibly leading to new therapies in the worldwide fight against obesity and diabetes.

“With this discovery, we now have a means of metabolic manipulation that could help speed energy production and lead to weight loss,” said senior author Barbara Kahn from the Beth Israel Deaconess Medical Center and the Harvard Medical School.

Writing in Nature, the Boston researchers’ said reducing the amount of the protein nicotinamide N-methyltransferase (NNMT) in the fat and liver cells of mice slowed the development of obesity and diabetes in mice. At the same time, they also confirmed that obese and diabetic mice had higher levels of NNMT in their liver and fat.

Structure of the NNMT protein (EMW via Wikimedia Commons)

Structure of the NNMT protein (EMW via Wikimedia Commons)

From this key piece of information, the researchers speculated that cutting down the levels of NNMT in these cells would speed up a series of metabolic reactions involving an organic compound called polyamines.

“Polyamines are a group of biological molecules that are found throughout the body, which have fundamental functions, including regulating cell growth,” said Daniel Kraus, a co-author of the study.

The accelerated metabolic reactions would increase the amount of calories the body burns as energy while at the same time would reduce the number of calories transformed into fat.

“While diet and exercise are important in controlling weight, anti-obesity therapies could be of tremendous help, and NNMT looks to be a promising target for future therapeutic development,” said Kahn.

Excessive Gamma Rays at Milky Way’s Center Hint at Dark Matter

Posted April 4th, 2014 at 6:59 pm (UTC+0)
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Artist rendering of the Fermi Gamma-ray Space Telescope. (NASA E/PO, Sonoma State University, Aurore Simonnet)

Artist rendering of the Fermi Gamma-ray Space Telescope. (NASA)

Scientists believe high-energy gamma rays emanating from the center of our Milky Way are being produced by dark matter, the mysterious hypothetical substance believed to make up most of the physical universe.

A new study based on independent research of gamma ray light shows that the center of our galaxy is cranking out huge amounts of these light emissions.

Gamma ray emissions are thought to be normally produced by sources such as interacting binary star systems (solar systems with two stars), isolated pulsars (rotating neutron stars), remnants of supernovae (exploding stars) and particles colliding with interstellar gas.

However, scientists have deduced other sources must be contributing to the massive output.

The researchers involved with the study, including scientists from NASA and Stanford and Harvard universities, believe this excess gamma radiation could be produced by dark matter.

A map of gamma rays detected in the galactic center by the Fermi Space Telescope. Red indicates the greatest number emissions. Prominent pulsars are labeled (left). Removing all known gamma-ray sources (right) reveals excess emission that may arise from dark matter annihilations. (T. Linden, Univ. of Chicago)

A map of gamma rays detected in the galactic center by the Fermi Space Telescope. Red indicates the greatest number emissions. Prominent pulsars are labeled (left). Removing all known gamma-ray sources (right) reveals excess emission that may arise from dark matter annihilations. (T. Linden, Univ. of Chicago)

“The new maps allow us to analyze the excess and test whether more conventional explanations, such as the presence of undiscovered pulsars or cosmic-ray collisions on gas clouds, can account for it,” said Dan Hooper, an astrophysicist at Fermilab in Batavia, Ill., and a lead author of the study. “The signal we find cannot be explained by currently proposed alternatives and is in close agreement with the predictions of very simple dark matter models.”

The scientists subtracted already known gamma ray sources from the amount of the high energy radiation coming out of the galactic center and found a remaining patch of leftover emissions (see photo right).

“This study is an example of innovative techniques applied to Fermi data by the science community,” said Peter Michelson, a Stanford University physics professor and the principal investigator for the Large Area Telescope (LAT), the principal scientific instrument on the Fermi Gamma Ray Space Telescope spacecraft. “The Fermi LAT Collaboration continues to examine the extraordinarily complex central region of the galaxy, but until this study is complete we can neither confirm nor refute this interesting analysis.”

While dark matter provides a convenient explanation for the gamma ray excess, the researchers point out it will take further investigation to confirm the role dark matter plays in the production of the excess gamma radiation. They also note continued research could reveal other possible alternative sources of the gamma rays that do not require dark matter.

This animation zooms into an image of the Milky Way, shown in visible light, and superimposes a gamma-ray map of the galactic center from NASA’s Fermi. Raw data transitions to a view with all known sources removed, revealing a gamma-ray excess hinting at the presence of dark matter. (NASA Goddard; A. Mellinger, CMU; T. Linden, Univ. of Chicago)

Flies Credited with Giving Zebras Their Stripes

Posted April 2nd, 2014 at 6:36 pm (UTC+0)
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A pair of zebras in Tanzania's Ruaha National Park (Paul Shaffner via Wikimedia Commons)

A pair of zebras in Tanzania’s Ruaha National Park. (Paul Shaffner via Wikimedia Commons)

Scientists say flies played a key role in the centuries-old mystery of how zebras came to have their distinguishing coat of black and white stripes.

Like humans and other primates whose fingerprints are unique to each individual, every zebra has its own distinctive set of striped markings.

The research team from the University of California, Davis tested five popular theories regarding zebras and their stripes and was able to reject all but one hypothesis.

Writing in Nature Communications, the researchers assert the zebra’s striped coating is the result of an evolutionary response to annoying and possibly harmful biting flies, such as horse flies and tsetse flies.

“I was amazed by our results,” said lead author Tim Caro, a University of California, Davis professor of wildlife biology. “Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies.“

Zebras developed their stripes flies like the tsetse fly (left) and the horse fly (right) from biting them (Alan R. Walker (left) Dennis Ray (right) via Wikimedia Commons)

Zebras developed their stripes to keep flies like the tsetse fly (left) and the horse fly (right) from biting them. (Alan R. Walker (left) Dennis Ray (right) via Wikimedia Commons)

Studies, including those conducted previously by the team, revealed that these fly species seemed to be most attracted to animals with dark solid coloring, while avoiding black-and-white striped surfaces. The researchers found these blood sucking flies were more attracted to solid dark surfaces that reflected light waves which were constant and oriented in the same direction. Scientists surmised the light waves reflected from dark surfaces were similar to those reflected from pools of water where the flies are known to lay their eggs. By contrast, striped surfaces might be less inviting to flies because they emit multiple light patterns.

The research team said evolution provided zebras with their stripes, while other hooved animals in the same vicinity remained stripe free, because the zebra’s hair is much shorter than the mouth part length of biting flies. This led the research team to think that zebras might especially vulnerable to the biting flies.

An up close look at a zebra's unique stripe covered coat. (William Warby via Flickr/Creative Commons)

An close-up look at a zebra’s unique stripe covered coat. (William Warby via Flickr/Creative Commons)

“No one knew why zebras have such striking coloration,” Caro said. “But solving evolutionary conundrums increases our knowledge of the natural world and may spark greater commitment to conserving it.”

While the team solved one mystery others remain to be explained, such as what prevents these blood sucking flies from seeing striped surfaces as potential prey, and why are zebras, in particular, so vulnerable to these annoying insects.

Other theories as to why zebras have stripes include that the stripes protect them from attack by hiding them in the grass or by visually confusing their predators; that they serve as a form of heat management; or provide the animals with a social function.

Study Links Obesity to How Well We Digest Carbs

Posted March 31st, 2014 at 6:14 pm (UTC+0)
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Starchy foods like breads, pasta and rice are rich in refined carbohydrates (Wikimedia Commons)

Starchy foods like breads, pasta and rice are rich in refined carbohydrates. (Wikimedia Commons)

Obesity may be genetically linked to how our bodies digest carbohydrates, according to a new study from Imperial College London.

The body uses carbohydrates from the food we eat to produce glucose, which is used to fuel bodily functions. The human body can either use this glucose right away or store it in the liver and muscles for when it’s needed.

In their study, published Nature Genetics, researchers examined the connection between body weight and a gene called AMY1,which produces an enzyme found in our saliva called salivary amylase. The enzyme goes to work as soon as we take our first bite; it’s one of the first steps the body takes to digest starchy food.

Usually our DNA contains two copies of this gene, but researchers have found that various regions throughout our DNA can carry any number of the AMY1 gene and that the quantity of this gene can also vary between different people. The researchers believe that the higher numbers of AMY1 found in humans today is an evolutionary response to the change in diets toward increased starch.

Working with colleagues at institutions in other parts of the world, the British researchers looked into the number of AMY1 copies present in the DNA of people from the UK, France, Sweden and Singapore.

The UK scientists began their research project by first analyzing genetic data from 481 members of a Swedish family. The family participants were selected by sibling pairs, where one was obese and the other was not.

The researchers used this data to develop a short list of genes whose differences in numbers within an individual’s DNA influenced that person’s body mass index (BMI). In analyzing this list, the scientists found the gene coding for the AMY1 gene was the one with the greatest influence on body weight.

Artist rendering of the structure of AMY1A (EMW via Wikimedia Commons)

Artist rendering of the structure of AMY1A (EMW via Wikimedia Commons)

With this finding in hand, they went on study about 5,000 more test subjects from France and the UK and looked into the association between the number of times the AMY1 gene was repeated on chromosome 1 in each of these people and their risk of obesity.

After checking for the amount of AMY1 copies contained in their test subject’s DNA, they noticed that those with a low number of the salivary enzyme producing gene had a greater chance of becoming obese.

The researchers then expanded their study to include approximately 700 people from Singapore, both obese and normal weight, and came up with the same results found with the European subjects.

The UK scientists found that people with fewer than four copies of the AMY1 had a nearly eight times higher chance of being obese that those who had nine or more copies within their DNA.

With every extra copy of the AMY1 gene a person had, the researchers estimated that there was approximately a 20 per cent decrease in the chances of that person becoming obese.

“I think this is an important discovery because it suggests that how we digest starch and how the end products from the digestion of complex carbohydrates behave in the gut could be important factors in the risk of obesity,” said Philippe Froguel of Imperial College London, one of the study’s lead authors. “Future research is needed to understand whether or not altering the digestion of starchy food might improve someone’s ability to lose weight, or prevent a person from becoming obese.”

obese-mainThe team is also interested in whether there’s a link between this genetic variation and people’s risk of other metabolic disorders such as diabetes.

Another study author, Mario Falchi, also from Imperial College London, said that while their study examined how our bodies physically digest carbohydrates, earlier genetic studies related to obesity focused on identifying differences in genes that act in the brain which control our appetites.

He said that the previous studies, combined with their new research, will allow scientists to find better ways of attacking obesity.

Science Images of the Month

Posted March 28th, 2014 at 8:25 pm (UTC+0)
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NASA/JPL's new Airborne Snow Observatory flys over the Tuolumne River Basin of California’s Sierra Nevada mountain range as it measures the snowpack’s depth and water content with precision amid California’s drought. (AP Photo/Haven Daley)

NASA’s new Airborne Snow Observatory flies over California’s Sierra Nevada mountain range as it measures the snowpack’s depth and water content amid California’s drought, March 23, 2014. (AP)

A very small version of the 20-gigapixel mosaic depicting part of the Milky Way.  The mosaic image was constructed from more than 2 million infrared snapshots taken over the past 10 years by NASA's Spitzer Space Telescope. (NASA)

On March 18, 2014,  NASA officials in Pasadena, Calif unveiled GLIMPSE360, a new website that offers a tour of the Milky Way with a new zoomable, 360-degree mosaic. The mosaic image was constructed from more than 2 million infrared snapshots taken over the past 10 years by NASA’s Spitzer Space Telescope. (NASA)

Engineers working inside the world's largest clean room located at NASA's Goddard Space Flight Center this week installed the Near Infrared Camera (NIRCam), into James Webb Space Telescope.  The NIRCam is considered to be an essential part of the new space telescope that's currently under construction. NASA is looking to launch the state of the art space telescope in 2018. (NASA/Chris Gunn)

Engineers work inside the world’s largest clean room at NASA’s Goddard Space Flight Center, on March 20, 2014, installing the Near Infrared Camera (NIRCam) into the James Webb Space Telescope, which is under construction and slated to launch in 2018. (NASA)

Researchers at the Georgia Institute of Technology recentlhy used this device that simulated blood flowing through narrowed coronary arteries to assess effects of anti-clotting drugs. (Rob Felt/GA Tech)

This past week researchers at the Georgia Institute of Technology said that they found that aspirin can prevent dangerous blood clots in some at-risk patients, it may not be effective in all patients with narrowed arteries. The researchers used this device that simulated blood flowing through narrowed coronary arteries to assess effects of anti-clotting drugs. (Rob Felt/GA Tech)

Images from NASA's Hubble Space telescope and Chandra X-Ray Observatory were assembled into a mosaic of the galaxy ESO 137-001 (top right) hurtling through massive galaxy cluster Abell 3627 which is some 220 million light years away. (NASA, ESA, CXC)

This mosaic photo, released March 4, 2014, shows the galaxy ESO 137-001 (top right) hurtling through massive galaxy cluster Abell 3627.  The mosaic was made from images taken by NASA’s Hubble Space telescope and Chandra X-Ray Observatory. This region of space is some 220 million light years away from Earth. (NASA)

Artists' reconstruction of Tamisiocaris borealis, an ancient marine animal that lived 520 million years ago during the Early Cambrian period. Research led by the University of Bristol UK that studied fossils of this creature found that they used some rather odd facial appendages to filter their food from the ocean. (Rob Nicholls, Palaeocreations)

Artists’ reconstruction of Tamisiocaris borealis, an ancient marine animal that lived 520 million years ago during the Early Cambrian period. On March 26, 2014, researchers from the University of Bristol in the UK, unveiled a new study that found that this creature used some rather odd facial appendages to filter their food from the ocean. (Rob Nicholls, Palaeocreations)

The Expedition 39 Soyuz rocket takes off from the Baikonur Cosmodrome Wednesday, March 26, 2014, in Baikonur, Kazakhstan. (AP/NASA)

The Expedition 39 Soyuz rocket takes off from the Baikonur Cosmodrome on March 26, 2014, in Baikonur, Kazakhstan. (AP/NASA)

Artists's concept of the ATHENA desktop human 'body' that's being built at the Los Alamos National Laboratory.  Scientists there say this device, that combines heart, liver, kidney and lung features, could reduce need for animal drug tests in checking a drug's toxicity. (Los Alamos National Laboratory)

Artist’s concept of the ATHENA desktop human body being built at the Los Alamos National Laboratory. The device, which combines heart, liver, kidney and lung features, could reduce need for animal drug tests when assessing a drug’s toxicity. (Los Alamos National Laboratory)

 

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