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Tuesday, September 1, 2015

Marijuana Toking Passes Cigarette Smoking Among College Students For The First Time, Pot Popularity Growing According To Drug Use Study



Daily marijuana use among the nation's college students is on the rise, surpassing daily cigarette smoking for the first time in 2014.

A series of national surveys of U.S. college students, as part of the University of Michigan's Monitoring the Future study, shows that marijuana use has been growing slowly on the nation's campuses since 2006.

A dried flower bud of the Cannabis plant.
Credit: Evan-Amos

Daily or near-daily marijuana use was reported by 5.9 percent of college students in 2014--the highest rate since 1980, the first year that complete college data were available in the study. This rate of use is up from 3.5 percent in 2007. In other words, one in every 17 college students is smoking marijuana on a daily or near-daily basis, defined as use on 20 or more occasions in the prior 30 days.

Other measures of marijuana use have also shown an increase: The percent using marijuana once or more in the prior 30 days rose from 17 percent in 2006 to 21 percent in 2014. Use in the prior 12 months rose from 30 percent in 2006 to 34 percent in 2014. Both of these measures leveled in 2014.

"It's clear that for the past seven or eight years there has been an increase in marijuana use among the nation's college students," said Lloyd Johnston, the principal investigator of the study. "And this largely parallels an increase we have been seeing among high school seniors."

Much of this increase may be due to the fact that marijuana use at any level has come to be seen as dangerous by fewer adolescents and young adults. For example, while 55 percent of all 19-to-22-year-old high school graduates saw regular marijuana use as dangerous in 2006, only 35 percent saw it as dangerous by 2014.

The study also found that the proportion of college students using any illicit drug, including marijuana, in the prior 12 months rose from 34 percent in 2006 to 41 percent in 2013 before falling off some to 39 percent in 2014. That seven-year increase was driven primarily by the increase in marijuana use, though marijuana was not the only drug on the rise.

The proportion of college students using any illicit drug other than marijuana in the prior 12 months increased from 15 percent in 2008--the recent low point--to 21 percent in 2014, including a continuing increase in 2014. The increase appears attributable mostly to college students' increased use of amphetamines (without a doctor's orders) and use of ecstasy.

These and other results about drug use come from Monitoring the Future, an annual survey that has been reporting on U.S. college students' substance use of all kinds for 35 years. The study began in 1980 and is conducted by the U-M Institute for Social Research with funding from the National Institute on Drug Abuse, one of the National Institutes of Health.

College students' nonmedical use of amphetamines in the prior 12 months nearly doubled between 2008 (when 5.7 percent said they used) and 2012 (when 11.1 percent used), before leveling at 10.1 percent in 2014.

"It seems likely that this increase in amphetamine use on the college campus resulted from more students using these drugs to try to improve their studies and test performance," Johnston said.

Their age-peer high school graduates not in college had higher-reported amphetamine use for many years (1983-2008), but after 2010, college students have had the higher rate of use.

"Fortunately, their use of these drugs appears to have leveled among college students, at least," he said.

Ecstasy (MDMA, sometimes called Molly), had somewhat of a comeback in use among college students from 2007 through 2012, with past 12-month use more than doubling from 2.2 percent in 2007 to 5.8 percent in 2012, before leveling. Previously, ecstasy had fallen from favor among college students. By 2004, it had fallen to quite low levels and then remained at low levels through 2007.

Past-year use of cocaine showed a statistically significant increase from 2.7 percent in 2013 to 4.4 percent in 2014.

"We are being cautious in interpreting this one-year increase, which we do not see among high school students; but we do see some increase in cocaine use in other young adult age bands, so there may in fact be an increase in cocaine use beginning to occur," Johnston said. "There is some more welcome news for parents as they send their children off to college this fall. Perhaps the most important is that five out of every 10 college students have not used any illicit drug in the past year, and more than three quarters have not used any in the prior month."

In addition, the use of synthetic marijuana (also called K-2 or spice) has been dropping sharply since its use was first measured in 2011. At that time, 7.4 percent of college students indicated having used synthetic marijuana in the prior 12 months; by 2014 the rate had fallen to just 0.9 percent, including a significant decline in use in 2014. One reason for the decline in synthetic drug use is that an increasing number of young people see it as dangerous.

Likewise, college students' use of salvia--a hallucinogenic plant which became popular in recent years--fell from an annual prevalence of 5.8 percent in 2009 to just 1.1 percent in 2014.

The nonmedical use of narcotic drugs--which has accounted for an increasing number of deaths in recent years according to official statistics--actually has been declining among college students, falling from 8.8 percent reporting past-year use in 2006 down to 4.8 percent by 2014. This is a particularly welcome improvement from a public health point of view, note the investigators.

There is no evidence of a shift over from narcotic drugs to heroin use in this population. Use of heroin has been very low among college students over the past five years or so--lower than it was in the late 1990s and early 2000s.

The non-medical use of tranquilizers by college students has fallen by nearly half since 2003, when 6.9 percent reported past-year use, to 2014, when 3.5 percent did.

The use of LSD and other hallucinogenic drugs, once popular in this age group, remains at low levels of use on campus, with past-year usage rates at 2.2 percent and 3.2 percent, respectively. And use of the so-called club drugs (Ketamine, GHB, Rohypnol) remains very low. Further, the use of so-called bath salts (synthetic stimulants often sold over the counter) never caught on among college students, who have a negligible rate of use.

In sum, quite a number of drugs have been fading in popularity on U.S. college campuses in recent years, and a similar pattern is found among youth who do not attend college. Two of the newer drugs, synthetic marijuana and salvia, have shown steep declines in use. Other drugs are showing more gradual declines, including narcotic drugs other than heroin, sedatives and tranquilizers--all used nonmedically--as well as inhalants and hallucinogens.

On the other hand, past-year and past-month marijuana use increased from 2006 through 2013 before leveling; and daily marijuana use continues to grow, reaching the highest level seen in the past 35 years in 2014 (5.9 percent). Amphetamine use grew fairly sharply on campus between 2008 and 2012, and it then stabilized at high levels not seen since the mid-1980s.

Ecstasy use has made somewhat of a rebound since the recent low observed among college students in 2007. Cocaine use among college students is well below the 1980s and 1990s rates, but the significant increase in 2014 among college students suggests a need to watch this drug carefully in the future.

ALCOHOL AND TOBACCO

Use of a number of licit drugs is also covered in the MTF surveys, including alcoholic beverages and various tobacco products.

While 63 percent of college students in 2014 said that they have had an alcoholic beverage at least once in the prior 30 days, that figure is down a bit from 67 percent in 2000 and down considerably from 82 percent in 1981. The proportion of the nation's college students saying they have been drunk in the past 30 days was 43 percent in 2014, down some from 48 percent in 2006.

Occasions of heavy or binge drinking--here defined as having five or more drinks in a row on at least one occasion in the prior two weeks--have consistently had a higher prevalence among college students than among their fellow high school classmates who are not in college.

Still, between 1980 and 2014, college students' rates of such drinking declined 9 percentage points from 44 percent to 35 percent, while their noncollege peers declined 12 percentage points from 41 percent to 29 percent, and high school seniors' rates declined 22 percentage points from 41 percent to 19 percent.

Of particular concern is the extent of extreme binge drinking in college, first defined as having 10 or more drinks in a row at least once in the prior two weeks, and then defined as having 15 or more drinks in a row in that same time interval. Based on the combined years 2005-2014, the estimates for these two behaviors among college students are 13 percent and 5 percent, respectively.

"Despite the modest improvements in drinking alcohol at college, there are still a sizable number of students who consume alcohol at particularly dangerous levels," Johnston said.

Cigarette smoking continued to decline among the nation's college students in 2014, when 13 percent said they had smoked one or more cigarettes in the prior 30 days, down from 14 percent in 2013 and from the recent high of 31 percent in 1999--a decline of more than half. As for daily smoking, only 5 percent indicated smoking at that level, compared with 19 percent in 1999--a drop of nearly three fourths in the number of college students smoking daily.

"These declines in smoking at college are largely the result of fewer of these students smoking when they were still in high school," Johnston said. "Nevertheless, it is particularly good news that their smoking rates have fallen so substantially."

Unfortunately, the appreciable declines in cigarette smoking have been accompanied by some increases in the use of other forms of tobacco or nicotine. Smoking tobacco using a hookah (a type of water pipe) in the prior 12 months rose substantially among college students, from 26 percent in 2013 to 33 percent in 2014.

In 2014, the use of e-cigarettes in the past 30 days stood at 9.7 percent, while use of flavored little cigars stood at 9.8 percent, of regular little cigars at 8.6 percent and of large cigars at 8.4 percent. The study will continue tracking the extent to which these alternate forms of tobacco use are changing in popularity, not only among college students, but also among their age peers not in college and among secondary school students.

###

The Monitoring the Future study is now in its 41st year and has surveyed nationally representative samples of full-time college students one to four years beyond high school each year for 35 years, starting in 1980. The annual samples of college students have ranged between 1,000 and 1,500 per year.

MTF is an investigator-initiated research undertaking, conceived and conducted by a group of research professors at the University of Michigan's Institute for Social Research (listed as authors below) and funded under a series of peer-reviewed, competitive research grants from the National Institute on Drug Abuse.

MTF also conducts an annual national survey of high school seniors, from which a random, nationally representative sub-sample is drawn for follow-up by mail in future years. Follow-up respondents one to four years past high school and who report being enrolled in college full-time comprise the college student sample. They are not drawn from particular colleges or universities, which helps to make the sample more representative of the wide range of two- and four-year institutions of higher education.


Contacts and sources:
University of Michigan

The findings presented here are drawn from Chapters 8 and 9 in the newly published monograph cited below: Johnston, L.D., O'Malley, P.M, Bachman, J.G., Schulenberg, J.E. & Miech, R. A. (2015). Monitoring the Future national survey results on drug use. 1975-2014: Volume 2, College students and adults ages 19-55. Ann Arbor: Institute for Social Research. The University of Michigan, 416 pp. Available at myumi.ch/J7G22.

How Earth-Like Are Potentially Habitable Exoplanets?

About 31 potentially habitable exoplanets have been discovered.   Four are confirmed and 27 remain to be confirmed.  Almost all of them are larger than Earth and fall into the category of a super-Earth. A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below the mass of the Solar System's ice giants Uranus and Neptune, which are 15 and 17 Earth masses respectively.
The term super-Earth refers only to the mass of the planet, and does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, as suggested by MIT professor Sara Seager, although mini-Neptunes is more common.

As astronomers continue finding new rocky planets around distant stars, high-pressure physicists are considering what the interiors of those planets might be like and how their chemistry could differ from that found on Earth. New work from a team including three Carnegie scientists demonstrates that different magnesium compounds could be abundant inside other planets as compared to Earth. Their work is published by Scientific Reports.

Oxygen and magnesium are the two most-abundant elements in Earth's mantle. However, when scientists are predicting the chemical compositions of rocky, terrestrial planets outside of our own Solar System, they shouldn't assume that other rocky planets would have Earth-like mantle mineralogy, according to a research team including Carnegie's Sergey Lobanov, Nicholas Holtgrewe, and Alexander Goncharov.

This is the crystal structure of magnesium peroxide, MgO2, courtesy of Sergey Lobanov, created using K. Momma's program for drawing crystal structures. 

Credit: Sergey Lobanov

Stars that have rocky planets are known to vary in chemical composition. This means that the mineralogies of these rocky planets are probably different from each other and from our own Earth, as well. For example, elevated oxygen contents have been observed in stars that host rocky planets. As such, oxygen may be more abundant in the interiors of other rocky planets, because the chemical makeup of a star would affect the chemical makeups of the planets that formed around it. If a planet is more oxidized than Earth, then this could affect the composition of the compounds found in its interior, too, including the magnesium compounds that are the subject of this study.

Magnesium oxide, MgO, is known to be remarkably stable, even under very high pressures. And it isn't reactive under the conditions found in Earth's lower mantle. Whereas magnesium peroxide, MgO2, can be formed in the laboratory under high-oxygen concentrations, but it is highly unstable when heated, as would be the case in a planetary interior.

Previous theoretical calculations had indicated that magnesium peroxide would become stable under high-pressure conditions. Taking that idea one step further, the team set out to test whether stable magnesium peroxide could be synthesized under extreme conditions mimicking planetary interiors.

Using a laser-heated, diamond-anvil cell, they brought very small samples of magnesium oxide and oxygen to different pressures meant to mimic planetary interiors, from ambient pressure to 1.6 million times normal atmospheric pressure (0-160 gigapascals), and heated them to temperatures above 3,140 degrees Fahrenheit (2,000 Kelvin). They found that under about 950,000 times normal atmospheric pressure (96 gigapascals) and at temperatures of 3,410 degrees Fahrenheit (2,150 Kelvin), magnesium oxide reacted with oxygen to form magnesium peroxide.

"Our findings suggest that magnesium peroxide may be abundant in extremely oxidized mantles and cores of rocky planets outside our Solar System," said Lobanov, the paper's lead author "When we develop theories about distant planets, it's important that we don't assume their chemistry and mineralogy is Earth-like."

"These findings provide yet another example of the ways that high-pressure laboratory experiments can teach us about not only our own planet, but potentially about distant ones as well," added Goncharov.

Because of its chemical inertness, MgO has also long been used as a conductor that transmits heat and pressure to an experimental sample. "But this new information about its chemical reactivity under high pressure means that such experimental uses of MgO need to be revised, because it they could be creating unwanted reactions and affecting results," Goncharov added.


Contacts and sources:
Sergey Lobanov
Carnegie Institution 

Magnetic Fields Are Innovative New Way To Communicate Wirelessly


Electrical engineers at the University of California, San Diego demonstrated a new wireless communication technique that works by sending magnetic signals through the human body. The new technology could offer a lower power and more secure way to communicate information between wearable electronic devices, providing an improved alternative to existing wireless communication systems, researchers said. They presented their findings Aug. 26 at the 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society in Milan, Italy.

This is a prototype of the magnetic field human body communication, developed in Mercier's Energy-Efficient Microsystems Lab at UC San Diego, consists of magnetic-field-generating coils wrapped around three parts of the body, including the head, arm and leg.

Credit: Jacobs School of Engineering, UC San Diego

While this work is still a proof-of-concept demonstration, researchers envision developing it into an ultra low power wireless system that can easily transmit information around the human body. An application of this technology would be a wireless sensor network for full-body health monitoring.

"In the future, people are going to be wearing more electronics, such as smart watches, fitness trackers and health monitors. All of these devices will need to communicate information with each other. Currently, these devices transmit information using Bluetooth radios, which use a lot of power to communicate. We're trying to find new ways to communicate information around the human body that use much less power," said Patrick Mercier, a professor in the Department of Electrical and Computer Engineering at UC San Diego who led the study. Mercier also serves as the co-director of the UC San Diego Center for Wearable Sensors.

Communicating magnetic signals through the human body

The new study presents a solution to some of the main barriers of other wireless communication systems: in order to reduce power consumption when transmitting and receiving information, wireless systems need to send signals that can easily travel from one side of the human body to another. Bluetooth technology uses electromagnetic radiation to transmit data, however these radio signals do not easily pass through the human body and therefore require a power boost to help overcome this signal obstruction, or "path loss."

In this study, electrical engineers demonstrated a technique called magnetic field human body communication, which uses the body as a vehicle to deliver magnetic energy between electronic devices. An advantage of this system is that magnetic fields are able to pass freely through biological tissues, so signals are communicated with much lower path losses and potentially, much lower power consumption. In their experiments, researchers demonstrated that the magnetic communication link works well on the body, but they did not test the technique's power consumption. Researchers showed that the path losses associated with magnetic field human body communication are upwards of 10 million times lower than those associated with Bluetooth radios.

"This technique, to our knowledge, achieves the lowest path losses out of any wireless human body communication system that's been demonstrated so far. This technique will allow us to build much lower power wearable devices," said Mercier.

Lower power consumption also leads to longer battery life. "A problem with wearable devices like smart watches is that they have short operating times because they are limited to using small batteries. With this magnetic field human body communication system, we hope to significantly reduce power consumption as well as how frequently users need to recharge their devices," said Jiwoong Park, a Ph.D student in Mercier's Energy-Efficient Microsystems Lab at the UC San Diego Jacobs School of Engineering and first author of the study.

The researchers also pointed out that this technique does not pose any serious health risks. Since this technique is intended for applications in ultra low power communication systems, the transmitting power of the magnetic signals sent through the body is expected to be many times lower than that of MRI scanners and wireless implant devices.

Another potential advantage of magnetic field human body communication is that it could offer more security than Bluetooth networks. Because Bluetooth radio communicates data over the air, anyone standing within 30 feet can potentially eavesdrop on that communication link. On the other hand, magnetic field human body communication employs the human body as a communication medium, making the communication link less vulnerable to eavesdropping. With this technique, researchers demonstrated that magnetic communication is strong on the body but dramatically decreases off the body. To put this in the context of a personal full-body wireless communication network, information would neither be radiated off the body nor be transmitted from one person to another.

"Increased privacy is desirable when you're using your wearable devices to transmit information about your health," said Park.

Demonstrating magnetic communication with a proof-of-concept prototype

The researchers built a prototype to demonstrate the magnetic field human body communication technique. The prototype consists of copper wires insulated with PVC tubes. On one end, the copper wires are hooked up to an external analyzer and on the other end, the wires are wrapped in coils around three areas of the body: the head, arms and legs. These coils serve as sources for magnetic fields and are able to send magnetic signals from one part of the body to another using the body as a guide. With this prototype, researchers were able to demonstrate and measure low path loss communication from arm to arm, from arm to head, and from arm to leg.

Researchers noted that a limitation of this technique is that magnetic fields require circular geometries in order to propagate through the human body. Devices like smart watches, headbands and belts will all work well using magnetic field human body communication, but not a small patch that is stuck on the chest and used to measure heart rate, for example. As long as the wearable application can wrap around a part of the body, it should work just fine with this technique, researchers explained.



Contacts and sources:
Liezel Labios
University of California, San Diego 

Monday, August 31, 2015

Giant Sea Scorpion Found in Iowa



The fossil of a previously unknown species of 'sea scorpion', measuring over 1.5 meters long, has been discovered in Iowa, USA, and described in the open-access journal BMC Evolutionary Biology.

This is an artist's impression Pentecopterus.

Credit: Patrick Lynch - Yale University

Dating back 460 million years, it is the oldest known species of eurypterid (sea scorpion) - extinct monster-like predators that swam the seas in ancient times and are related to modern arachnids.

The authors named the new species Pentecopterus decorahensis after the 'penteconter' - an ancient Greek warship that the species resembles in outline and parallels in its predatory behavior.

These are Pentecopterus hairs. Scale bar 1 mm.

Credit: James Lamsdell

Lead author, James Lamsdell from Yale University, USA, said: "The new species is incredibly bizarre. The shape of the paddle - the leg which it would use to swim - is unique, as is the shape of the head. It's also big - over a meter and a half long!"

He adds: "Perhaps most surprising is the fantastic way it is preserved - the exoskeleton is compressed on the rock but can be peeled off and studied under a microscope. This shows an amazing amount of detail, such as the patterns of small hairs on the legs. At times it seems like you are studying the shed skin of a modern animal - an incredibly exciting opportunity for any paleontologist."

The new eurypterid species is represented by more than 150 fossil fragments, excavated from the upper layer of the Winneshiek Shale in northeastern Iowa - a 27 meter thick sandy shale located within an ancient meteorite impact crater and mostly submerged by the Upper Iowa River.

Some large body segments suggest a total length of up to 1.7 meters, making Pentecopterusthe largest known eurypterid from its era.

Pentecopterus is about 460 million years old, making it ten million years older than the previous oldest record of the eurypterid group.

This is a Pentecopterus leg. Scale bar 1 cm.

Credit: James Lamsdell

Some features of Pentecopterus revealed in the fossils also allow the researchers to interpret the functions of certain body parts. The rearmost limbs include a paddle with a large surface area, and joints that appear to be locked in place to reduce flex. This suggests that Pentecopterus used these paddles to either swim or dig.

The second and third pairs of limbs may have been angled forward, suggesting that they were involved primarily in prey capture rather than locomotion. The three rearmost pairs of limbs are shorter than the front pairs, suggesting that Pentecopterus may have walked on six legs rather than eight.

The exceptional preservation of the exoskeleton also helped the researchers to interpret the role of finer structures, including scales, follicles and setae (stiff bristles).

The rearmost limbs are covered in dense setae. These form arrangements similar to swimming crabs, where they function to expand the surface area of the paddle during swimming. But the smaller follicle size in eurypterids suggests that the setae could have had a sensory function.
Spines are also present on some limbs and appear similar to those found on horseshoe crabs where they aid in processing food.



Contacts and sources:
Joel Winston
BMC Evolutionary Biology

The Human Body Has Gone Through Four Stages of Evolution Says Study

Research into 430,000-year-old fossils collected in northern Spain found that the evolution of the human body's size and shape has gone through four main stages, according to a paper published this week.

A large international research team including Binghamton University anthropologist Rolf Quam studied the body size and shape in the human fossil collection from the site of the Sima de los Huesos in the Sierra de Atapuerca in northern Spain. Dated to around 430,000 years ago, this site preserves the largest collection of human fossils found to date anywhere in the world. 

Credit: Pass NCEA

The researchers found that the Atapuerca individuals were relatively tall, with wide, muscular bodies and less brain mass relative to body mass compared to Neanderthals. The Atapuerca humans shared many anatomical features with the later Neanderthals not present in modern humans, and analysis of their postcranial skeletons (the bones of the body other than the skull) indicated that they are closely related evolutionarily to Neanderthals.

"This is really interesting since it suggests that the evolutionary process in our genus is largely characterized by stasis (i.e. little to no evolutionary change) in body form for most of our evolutionary history," wrote Quam.

Comparison of the Atapuerca fossils with the rest of the human fossil record suggests that the evolution of the human body has gone through four main stages, depending on the degree of arboreality (living in the trees) and bipedalism (walking on two legs). The Atapuerca fossils represent the third stage, with tall, wide and robust bodies and an exclusively terrestrial bipedalism, with no evidence of arboreal behaviors. This same body form was likely shared with earlier members of our genus, such as Homo erectus, as well as some later members, including the Neanderthals. Thus, this body form seems to have been present in the genus Homo for over a million years.

It was not until the appearance of our own species, Homo sapiens, when a new taller, lighter and narrower body form emerged. Thus, the authors suggest that the Atapuerca humans offer the best look at the general human body shape and size during the last million years before the advent of modern humans.



Contacts and sources: 
John Brhel
Binghamton University

The study, titled "Postcranial morphology of the middle Pleistocene humans from Sima de los Huesos, Spain," was published in Proceedings of the National Academy of Sciences.

99% of All Seabirds Will Have Plastic in Their Gut by 2050, 60% Have It Now

Researchers from CSIRO and Imperial College London have assessed how widespread the threat of plastic is for the world's seabirds, including albatrosses, shearwaters and penguins, and found the majority of seabird species have plastic in their gut.

The study, led by Dr Chris Wilcox with co-authors Dr Denise Hardesty and Dr Erik van Sebille and published today in the journal PNAS, found that nearly 60 per cent of all seabird species have plastic in their gut.

A red-footed booby on Christmas Island, in the Indian Ocean.
Credit: © CSIRO, Britta Denise Hardesty

Based on analysis of published studies since the early 1960s, the researchers found that plastic is increasingly common in seabird's stomachs.

In 1960, plastic was found in the stomach of less than 5 per cent of individual seabirds, rising to 80 per cent by 2010.

The researchers predict that plastic ingestion will affect 99 per cent of the world's seabird species by 2050, based on current trends.

The scientists estimate that 90 per cent of all seabirds alive today have eaten plastic of some kind.

This includes bags, bottle caps, and plastic fibres from synthetic clothes, which have washed out into the ocean from urban rivers, sewers and waste deposits.

Birds mistake the brightly coloured items for food, or swallow them by accident, and this causes gut impaction, weight loss and sometimes even death.

"For the first time, we have a global prediction of how wide-reaching plastic impacts may be on marine species - and the results are striking," senior research scientist at CSIRO Oceans and Atmosphere Dr Wilcox said.

Plastic fragments washing in the surf on Christmas Island, in the northeastern Indian Ocean.
Credit: © CSIRO, Britta Denise Hardesty

"We predict, using historical observations, that 90 per cent of individual seabirds have eaten plastic. This is a huge amount and really points to the ubiquity of plastic pollution."

Dr Denise Hardesty from CSIRO Oceans and Atmosphere said seabirds were excellent indicators of ecosystem health.

"Finding such widespread estimates of plastic in seabirds is borne out by some of the fieldwork we've carried out where I've found nearly 200 pieces of plastic in a single seabird," Dr Hardesty said.

The researchers found plastics will have the greatest impact on wildlife where they gather in the Southern Ocean, in a band around the southern edges of Australia, South Africa and South America.

Dr van Sebille, from the Grantham Institute at Imperial College London, said the plastics had the most devastating impact in the areas where there was the greatest diversity of species.

"We are very concerned about species such as penguins and giant albatrosses, which live in these areas," Erik van Sebille said.

"While the infamous garbage patches in the middle of the oceans have strikingly high densities of plastic, very few animals live here."

Dr Hardesty said there was still the opportunity to change the impact plastic had on seabirds.

"Improving waste management can reduce the threat plastic is posing to marine wildlife," she said.

"Even simple measures can make a difference. Efforts to reduce plastics losses into the environment in Europe resulted in measureable changes in plastic in seabird stomachs with less than a decade, which suggests that improvements in basic waste management can reduce plastic in the environment in a really short time."

Chief Scientist at the US-based Ocean Conservancy Dr George H. Leonard said the study was highly important and demonstrated how pervasive plastics were in oceans.

"Hundreds of thousands of volunteers around the world come face-to-face with this problem during annual Coastal Cleanup events," Dr Leonard said.

"Scientists, the private sector and global citizens working together against the growing onslaught of plastic pollution can reduce plastic inputs to help protect marine biodiversity."



Contacts and sources:
Simon Torok
CSIRO 

Mummified Life Found Deep Beneath the Ocean Floor, Like Life Found at "Lost City"

Ancient rocks harbored microbial life deep below the seafloor, reports a team of scientists from the Woods Hole Oceanographic Institution (WHOI), Virginia Tech, and the University of Bremen. This new evidence was contained in drilled rock samples of Earth's mantle - thrust by tectonic forces to the seafloor during the Early Cretaceous period. The new study was published today in the Proceedings of the National Academy of Sciences.

Scientist found mummified microbial life in rocks from a seafloor hydrothermal system that was active more than 100 million years ago during the Early Cretaceous when the supercontinent Pangaea was breaking apart and the Atlantic ocean was just about to open. Buried under almost 700 meters of sediment, the samples were recovered by the seafloor drilling vessel JOIDES Resolution near the coast of Portugal. Hydrothermal fluids rich in hydrogen and methane mixed with seawater about 65 meters below the seafloor. This process supported bacteria and archaea in what scientists call 'the deep biosphere' in rocks from Earth's mantle. Conditions for microbial life were nearly ideal, the study showed, in this seemingly inhospitable environment.

Credit: Illustration by Jack Cook, Woods Hole Oceanographic Institution. Inset paleogeographic reconstruction by Ron Blakey, Colorado Plateau Geosystems

The discovery confirms a long-standing hypothesis that interactions between mantle rocks and seawater can create potential for life even in hard rocks deep below the ocean floor. The fossilized microbes are likely the same as those found at the active Lost City hydrothermal field, providing potentially important clues about the conditions that support 'intraterrestrial' life in rocks below the seafloor.

"We were initially looking at how seawater interacts with mantle rocks, and how that process generates hydrogen," said Frieder Klein, an associate scientist at WHOI and lead author of the study. "But during our analysis of the rock samples, we discovered organic-rich inclusions that contained lipids, proteins and amino acids - the building blocks of life - mummified in the surrounding minerals."

These remarkable rocks, recovered by the Ocean Drilling Program (ODP) on board the drilling vessel JOIDES Resolution, are from the Earth's upper mantle that underwent intense alteration by heated seawater. The rocks show a systematic change in color from rusty brown (top) to green and black (bottom), reflecting the chemical gradients across the fluid mixing zone. These chemical gradients played a key role in supporting microbes with chemical energy and the substrates they needed to thrive. Fossilized microbes were found in white veins consisting of the minerals calcite and brucite.
Photo courtesy of Ocean Drilling Program

This study, which was a collaborative effort between Klein, WHOI scientists Susan Humphris, Weifu Guo and William Orsi, Esther Schwarzenbach from Virginia Tech and Florence Schubotz from the University of Bremen, focused on mantle rocks that were originally exposed to seawater approximately 125 million years ago when a large rift split the massive supercontinent known as Pangaea. The rift, which eventually evolved into the Atlantic Ocean, pulled mantle rocks from Earth's interior to the seafloor, where they underwent chemical reactions with seawater, transforming the seawater into a hydrothermal fluid.

"The hydrothermal fluid likely had a high pH and was depleted in carbon and electron acceptors," Klein said. "These extreme chemical conditions can be challenging for microbes. However, the hydrothermal fluid contained hydrogen and methane and seawater contains dissolved carbon and electron acceptors. So when you mix the two in just the right proportions, you can have the ingredients to support life."

According to Dr. Everett Shock, a professor at Arizona State University's School of Earth and Science Exploration, the study underscores the influence major geologic processes can have on the prospect for life.

"This research makes the connection all the way from convection of the mantle to the break-up of the continents to ultimately providing geochemical options for microbiology," Shock said. "It's just such a nice demonstration of real-world geobiology with a lot of 'geo' in it."

Drilling Deep

The rock samples analyzed in the study were originally drilled from the Iberian continental margin off the coast of Spain and Portugal in 1993. During the expedition aboard the research vessel JOIDES Resolution operated by the Ocean Drilling Program (ODP) - researchers drilled through 690 meters of mud and sediment deposited onto to the ocean floor to reach the ancient seafloor created during the break-up of the supercontinent Pangaea and the opening of the Atlantic Ocean. The drill samples had been stored in core repositories at room temperature for more than two decades, before Klein and his colleagues began their investigation and discovered the fossilized microbial remains.

"Colonies of bacteria and archaea were feeding off the seawater-hydrothermal fluid mix and became engulfed in the minerals growing in the fractured rock," Klein said. "This kept them completely isolated from the environment. The minerals proved to be the ultimate storage containers for these organisms, preserving their lipids and proteins for over 100 million years."

"It's exciting that the research team was able to go back and examine samples that had been collected years ago for other reasons and find new discoveries," Shock said. "There will always be active new drilling, but this study raises the possibility of there being a lot more out there in the way of existing samples that could be analyzed."

In the lab, samples from the rock interior had to be extracted since the outside of the drill core was stored under non-sterile conditions. So Klein and his colleagues took a number of careful steps to ensure the integrity of the sample interior wasn't compromised, and then analyzed the rocks with high-resolution microscopes, a confocal Raman spectrometer and a range of isotope techniques.

A Link to the Lost City

While Raman spectroscopy enabled Klein to verify the presence of amino acids, proteins and lipids in the samples, it did not provide enough detailed information to correlate them with other hydrothermal systems. The lipids were of particular interest to Klein since they tend to be better preserved over long timescales, and have been studied in a wide range of seafloor environments. This prompted Klein to ask Schubotz, an expert in lipid biomarker analysis at the University of Bremen, if she could tease out further information about the lipids from these ancient rocks.

Schubotz ran the lipids through an advanced liquid chromatography-based mass spectrometer system to separate out and identify their biochemical components. The analysis led to a remarkable discovery: the lipids from the Iberian margin match up with those from the Lost City hydrothermal field, which was discovered in 2000 in the Mid-Atlantic Ridge during an expedition on board the WHOI-operated research vessel Atlantis. This is significant because researchers believe the Lost City is a present-day analog to ancient hydrothermal systems on early Earth where life may have emerged.

The active Lost City hydrothermal field, located at the Mid-Atlantic Ridge, is hosted by rocks very similar to those from the Iberia continental margin analyzed in this study. Lost City will be drilled during a forthcoming expedition by the International Ocean Discovery Program (IODP). Klein and his colleagues hope to gain more detailed insight in the subseafloor life by comparing rocks from the Iberia continental margin with those from other ODP and IODP drill cores.
Photo by National Science Foundation, Univ. of Washington, Woods Hole Oceanographic Institution

"I was stoked when I saw Dr. Schubotz's email detailing the analytical results," Klein said. "It was fascinating to find these particular biological substances - which had previously been found only at the Lost City hydrothermal field and in cold seeps - in rocks below the seafloor where life is extremely challenging. At that point we knew we were onto something really cool!"

A Deeper Understanding

According to Klein, confirmation that life is possible in mantle rocks deep below the seafloor may have important implications for understanding subseafloor life across a wide range of geologic environments.

"All the ingredients necessary to drive these ecosystems were made entirely from scratch," he said. "Similar systems have likely existed throughout most of Earth's history to the present day and possibly exist(ed) on other water-bearing rocky planetary bodies, such as Jupiter's moon Europa."

The study reinforces the idea that life springs up anywhere there is water, even in seemingly hostile geological environments - a tantalizing prospect as scientists find more and more water elsewhere in the solar system. But Klein contends that, while scientists have long understood many of the forces driving microbial life above the seafloor, there is still a great deal of uncertainty when it comes to understanding biogeochemical processes occurring in the oceanic basement.

"In the future, we'll be trying to learn more about these particular microorganisms and what the environmental conditions were in the mixing zone in that location. We also plan to go to different places where we think similar processes may have taken place, such as along the Newfoundland margin, and analyze samples to see if we find similar signatures. Broadening this research could provide additional insights about Earth's history and the search for life in the solar system."


Contacts and sources:
Woods Hole Oceanographic Institution (WHOI)

Saturday, August 29, 2015

NASA Team Selects Potential Kuiper Belt Object for New Horizons Flyby Target, A Billion Miles from Pluto

NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits nearly a billion miles beyond Pluto.

Artist's impression of NASA's New Horizons spacecraft encountering a Pluto-like object in the distant Kuiper Belt.
Credits: NASA/JHUAPL/SwRI/Alex Parker

This remote KBO was one of two identified as potential destinations and the one recommended to NASA by the New Horizons team. Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science.

“Even as the New Horizon’s spacecraft speeds away from Pluto out into the Kuiper Belt, and the data from the exciting encounter with this new world is being streamed back to Earth, we are looking outward to the next destination for this intrepid explorer,” said John Grunsfeld, astronaut and chief of the NASA Science Mission Directorate at the agency headquarters in Washington. “While discussions whether to approve this extended mission will take place in the larger context of the planetary science portfolio, we expect it to be much less expensive than the prime mission while still providing new and exciting science.”

Like all NASA missions that have finished their main objective but seek to do more exploration, the New Horizons team must write a proposal to the agency to fund a KBO mission. That proposal – due in 2016 – will be evaluated by an independent team of experts before NASA can decide about the go-ahead.

Early target selection was important; the team needs to direct New Horizons toward the object this year in order to perform any extended mission with healthy fuel margins. New Horizons will perform a series of four maneuvers in late October and early November to set its course toward 2014 MU69 – nicknamed “PT1” (for “Potential Target 1”) – which it expects to reach on January 1, 2019. Any delays from those dates would cost precious fuel and add mission risk.

“2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”

New Horizons was originally designed to fly beyond the Pluto system and explore additional Kuiper Belt objects. The spacecraft carries extra hydrazine fuel for a KBO flyby; its communications system is designed to work from far beyond Pluto; its power system is designed to operate for many more years; and its scientific instruments were designed to operate in light levels much lower than it will experience during the 2014 MU69 flyby.”

The 2003 National Academy of Sciences’ Planetary Decadal Survey (“New Frontiers in the Solar System”) strongly recommended that the first mission to the Kuiper Belt include flybys of Pluto and small KBOs, in order to sample the diversity of objects in that previously unexplored region of the solar system. The identification of PT1, which is in a completely different class of KBO than Pluto, potentially allows New Horizons to satisfy those goals.

But finding a suitable KBO flyby target was no easy task. Starting a search in 2011 using some of the largest ground-based telescopes on Earth, the New Horizons team found several dozen KBOs, but none were reachable within the fuel supply available aboard the spacecraft.

The powerful Hubble Space Telescope came to the rescue in summer 2014, discovering five objects, since narrowed to two, within New Horizons’ flight path. Scientists estimate that PT1 is just under 30 miles (about 45 kilometers) across; that’s more than 10 times larger and 1,000 times more massive than typical comets, like the one the Rosetta mission is now orbiting, but only about 0.5 to 1 percent of the size (and about 1/10,000th the mass) of Pluto. As such, PT1 is thought to be like the building blocks of Kuiper Belt planets such as Pluto.

Path of NASA's New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, nicknamed "PT1" (for "Potential Target 1") by the New Horizons team. NASA must approve any New Horizons extended mission to explore a KBO.

Credits: NASA/JHUAPL/SwRI/Alex Parker

Unlike asteroids, KBOs have been heated only slightly by the Sun, and are thought to represent a well preserved, deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago.

“There’s so much that we can learn from close-up spacecraft observations that we’ll never learn from Earth, as the Pluto flyby demonstrated so spectacularly,” said New Horizons science team member John Spencer, also of SwRI. “The detailed images and other data that New Horizons could obtain from a KBO flyby will revolutionize our understanding of the Kuiper Belt and KBOs.”

The New Horizons spacecraft – currently 3 billion miles [4.9 billion kilometers] from Earth – is just starting to transmit the bulk of the images and other data, stored on its digital recorders, from its historic July encounter with the Pluto system. The spacecraft is healthy and operating normally.

New Horizons is part of NASA’s New Frontiers Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Ala. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate. SwRI leads the science mission, payload operations, and encounter science planning. 


Contacts and sources:
Tricia Talbert
NASA

Artificial Leaf Harnesses Produces Fuel Efficiently Using Sunlight

Generating and storing renewable energy, such as solar or wind power, is a key barrier to a clean-energy economy. When the Joint Center for Artificial Photosynthesis (JCAP) was established at Caltech and its partnering institutions in 2010, the U.S. Department of Energy (DOE) Energy Innovation Hub had one main goal: a cost-effective method of producing fuels using only sunlight, water, and carbon dioxide, mimicking the natural process of photosynthesis in plants and storing energy in the form of chemical fuels for use on demand.

Illustration of an efficient, robust and integrated solar-driven prototype featuring protected photoelectrochemical assembly coupled with oxygen and hydrogen evolution reaction catalysts. 
Credit: Image provided courtesy of Joint Center for Artificial Photosynthesis; artwork by Darius Siwek. 

Over the past five years, researchers at JCAP have made major advances toward this goal, and they now report the development of the first complete, efficient, safe, integrated solar-driven system for splitting water to create hydrogen fuels.

"This result was a stretch project milestone for the entire five years of JCAP as a whole, and not only have we achieved this goal, we also achieved it on time and on budget," says Caltech's Nate Lewis, George L. Argyros Professor and professor of chemistry, and the JCAP scientific director.

The new solar fuel generation system, or artificial leaf, is described in the August 27 online issue of the journal Energy and Environmental Science. The work was done by researchers in the laboratories of Lewis and Harry Atwater, director of JCAP and Howard Hughes Professor of Applied Physics and Materials Science.

"This accomplishment drew on the knowledge, insights and capabilities of JCAP, which illustrates what can be achieved in a Hub-scale effort by an integrated team," Atwater says. "The device reported here grew out of a multi-year, large-scale effort to define the design and materials components needed for an integrated solar fuels generator."

Solar Fuels Prototype in Operation
A fully integrated photoelectrochemical device performing unassisted solar water splitting for the production of hydrogen fuel. 
Credit: Erik Verlage and Chengxiang Xiang/Caltech

The new system consists of three main components: two electrodes—one photoanode and one photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules, generating protons and electrons as well as oxygen gas. The photocathode recombines the protons and electrons to form hydrogen gas. A key part of the JCAP design is the plastic membrane, which keeps the oxygen and hydrogen gases separate. If the two gases are allowed to mix and are accidentally ignited, an explosion can occur; the membrane lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.

Semiconductors such as silicon or gallium arsenide absorb light efficiently and are therefore used in solar panels. However, these materials also oxidize (or rust) on the surface when exposed to water, so cannot be used to directly generate fuel. A major advance that allowed the integrated system to be developed was previous work in Lewis's laboratory, which showed that adding a nanometers-thick layer of titanium dioxide (TiO2)—a material found in white paint and many toothpastes and sunscreens—onto the electrodes could prevent them from corroding while still allowing light and electrons to pass through. The new complete solar fuel generation system developed by Lewis and colleagues uses such a 62.5-nanometer-thick TiO2 layer to effectively prevent corrosion and improve the stability of a gallium arsenide–based photoelectrode.

Another key advance is the use of active, inexpensive catalysts for fuel production. The photoanode requires a catalyst to drive the essential water-splitting reaction. Rare and expensive metals such as platinum can serve as effective catalysts, but in its work the team discovered that it could create a much cheaper, active catalyst by adding a 2-nanometer-thick layer of nickel to the surface of the TiO2. This catalyst is among the most active known catalysts for splitting water molecules into oxygen, protons, and electrons and is a key to the high efficiency displayed by the device.

A highly efficient photoelectrochemical (PEC) device uses the power of the sun to split water into hydrogen and oxygen. The stand-alone prototype includes two chambers separated by a semi-permeable membrane that allows collection of both gas products.
Credit: Lance Hayashida/Caltech 


The photoanode was grown onto a photocathode, which also contains a highly active, inexpensive, nickel-molybdenum catalyst, to create a fully integrated single material that serves as a complete solar-driven water-splitting system.

A critical component that contributes to the efficiency and safety of the new system is the special plastic membrane that separates the gases and prevents the possibility of an explosion, while still allowing the ions to flow seamlessly to complete the electrical circuit in the cell. All of the components are stable under the same conditions and work together to produce a high-performance, fully integrated system. The demonstration system is approximately one square centimeter in area, converts 10 percent of the energy in sunlight into stored energy in the chemical fuel, and can operate for more than 40 hours continuously.

"This new system shatters all of the combined safety, performance, and stability records for artificial leaf technology by factors of 5 to 10 or more ," Lewis says.

(From left to right): Chengxiang Xiang and Erik Verlage assemble a monolithically integrated III-V device, protected by a TiO2 stabilization layer, which performs unassisted solar water splitting with collection of hydrogen fuel and oxygen.

Credit:  Lance Hayashida/Caltech

"Our work shows that it is indeed possible to produce fuels from sunlight safely and efficiently in an integrated system with inexpensive components," Lewis adds, "Of course, we still have work to do to extend the lifetime of the system and to develop methods for cost-effectively manufacturing full systems, both of which are in progress."

Because the work assembled various components that were developed by multiple teams within JCAP, coauthor Chengxiang Xiang, who is co-leader of the JCAP prototyping and scale-up project, says that the successful end result was a collaborative effort. "JCAP's research and development in device design, simulation, and materials discovery and integration all funneled into the demonstration of this new device," Xiang says.

These results are published in a paper titled "A monolithically integrated, intrinsically safe, 10% efficient, solar-driven water-splitting system based on active, stable earth-abundant electrocatalysts in conjunction with tandem III-V light absorbers protected by amorphous TiO2 films." In addition to Lewis, Atwater, and Xiang, other Caltech coauthors include graduate student Erik Verlage, postdoctoral scholars Shu Hu and Ke Sun, material processing and integration research engineer Rui Liu, and JCAP mechanical engineer Ryan Jones. Funding was provided by the Office of Science at the U.S. Department of Energy, and the Gordon and Betty Moore Foundation.


Contacts and sources:
Judy Asbury
Caltech
Written by Jessica Stoller-Conrad

Researchers See Quantum Motion For the First Time


Consider the pendulum of a grandfather clock. If you forget to wind it, you will eventually find the pendulum at rest, unmoving. However, this simple observation is only valid at the level of classical physics—the laws and principles that appear to explain the physics of relatively large objects at human scale. However, quantum mechanics, the underlying physical rules that govern the fundamental behavior of matter and light at the atomic scale, state that nothing can quite be completely at rest.

Credit: Chan Lei and Keith Schwab/Caltech

For the first time, a team of Caltech researchers and collaborators has found a way to observe—and control—this quantum motion of an object that is large enough to see. Their results are published in the August 27 online issue of the journal Science.

Researchers have known for years that in classical physics, physical objects indeed can be motionless. Drop a ball into a bowl, and it will roll back and forth a few times. Eventually, however, this motion will be overcome by other forces (such as gravity and friction), and the ball will come to a stop at the bottom of the bowl.

"In the past couple of years, my group and a couple of other groups around the world have learned how to cool the motion of a small micrometer-scale object to produce this state at the bottom, or the quantum ground state," says Keith Schwab, a Caltech professor of applied physics, who led the study. "But we know that even at the quantum ground state, at zero-temperature, very small amplitude fluctuations—or noise—remain."

Because this quantum motion, or noise, is theoretically an intrinsic part of the motion of all objects, Schwab and his colleagues designed a device that would allow them to observe this noise and then manipulate it.

The micrometer-scale device consists of a flexible aluminum plate that sits atop a silicon substrate. The plate is coupled to a superconducting electrical circuit as the plate vibrates at a rate of 3.5 million times per second. According to the laws of classical mechanics, the vibrating structures eventually will come to a complete rest if cooled to the ground state.

But that is not what Schwab and his colleagues observed when they actually cooled the spring to the ground state in their experiments. Instead, the residual energy—quantum noise—remained.

"This energy is part of the quantum description of nature—you just can't get it out," says Schwab. "We all know quantum mechanics explains precisely why electrons behave weirdly. Here, we're applying quantum physics to something that is relatively big, a device that you can see under an optical microscope, and we're seeing the quantum effects in a trillion atoms instead of just one."

Because this noisy quantum motion is always present and cannot be removed, it places a fundamental limit on how precisely one can measure the position of an object.

But that limit, Schwab and his colleagues discovered, is not insurmountable. The researchers and collaborators developed a technique to manipulate the inherent quantum noise and found that it is possible to reduce it periodically. Coauthors Aashish Clerk from McGill University and Florian Marquardt from the Max Planck Institute for the Science of Light proposed a novel method to control the quantum noise, which was expected to reduce it periodically. This technique was then implemented on a micron-scale mechanical device in Schwab's low-temperature laboratory at Caltech.

"There are two main variables that describe the noise or movement," Schwab explains. "We showed that we can actually make the fluctuations of one of the variables smaller—at the expense of making the quantum fluctuations of the other variable larger. That is what's called a quantum squeezed state; we squeezed the noise down in one place, but because of the squeezing, the noise has to squirt out in other places. But as long as those more noisy places aren't where you're obtaining a measurement, it doesn't matter."

The ability to control quantum noise could one day be used to improve the precision of very sensitive measurements, such as those obtained by LIGO, the Laser Interferometry Gravitational-wave Observatory, a Caltech-and-MIT-led project searching for signs of gravitational waves, ripples in the fabric of space-time.

"We've been thinking a lot about using these methods to detect gravitational waves from pulsars—incredibly dense stars that are the mass of our sun compressed into a 10 km radius and spin at 10 to 100 times a second," Schwab says. "In the 1970s, Kip Thorne [Caltech's Richard P. Feynman Professor of Theoretical Physics, Emeritus] and others wrote papers saying that these pulsars should be emitting gravity waves that are nearly perfectly periodic, so we're thinking hard about how to use these techniques on a gram-scale object to reduce quantum noise in detectors, thus increasing the sensitivity to pick up on those gravity waves," Schwab says.

In order to do that, the current device would have to be scaled up. "Our work aims to detect quantum mechanics at bigger and bigger scales, and one day, our hope is that this will eventually start touching on something as big as gravitational waves," he says.

These results were published in an article titled, "Quantum squeezing of motion in a mechanical resonator." In addition to Schwab, Clerk, and Marquardt, other coauthors include former graduate student Emma E. Wollman (PhD '15); graduate students Chan U. Lei and Ari J. Weinstein; former postdoctoral scholar Junho Suh; and Andreas Kronwald of Friedrich-Alexander-Universität in Erlangen, Germany. The work was funded by the National Science Foundation (NSF), the Defense Advanced Research Projects Agency, and the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center that also has support from the Gordon and Betty Moore Foundation.



Contacts and sources:
Judy Asbury
Caltech
Written by Jessica Stoller-Conrad


One of the most pressing issues in modern biological conservation is "invasion biology". Due to unprecedented contacts between peoples and culture in today's "global village" certain animal and plant species are spreading widely throughout the world, often causing enormous damage to local species.

This is the structure of Iron Age Floral List at each site. Circle size reflects the total number of new plant species recognized in Iron Age sites. Red indicates new species that appeared only in Philistine Iron Age sites. Green indicates species that appeared only in non-Philistine Iron Age contexts. Blue denotes species shared by Philistine and non-Philistine sites. The three numbers represent the quantity of Philistine species/non-Philistine species/shared species, at a site.
Credit: Map produced by M. Frumin using ArcGIS for Desktop (ArcMap 10.1), ESRI.

Recent studies have shown that alien species have had a substantial impact not only in recent times but also in antiquity. This is exemplified in a study published in the August 25th issue of Scientific Reports by a team led by archaeologists from Bar-Ilan University's Martin (Szusz) Department of Land of Israel Studies and Archaeology (Suembikya (Sue) Frumin, Prof. Ehud Weiss and Prof. Aren Maeir) and the Hebrew University (Dr. Liora Kolska Horwitz), describing the bio-archaeological remains of the

Philistine culture during the Iron Age (12th century to 7th century BCE). The team compiled a database of plant remains extracted from Bronze and Iron Ages sites in the southern Levant, both Philistine and non-Philistine. By analyzing this database, the researchers concluded that the Philistines brought to Israel not just themselves but also their plants.

The species they brought are all cultivars that had not been seen in Israel previously. This includes edible parts of the opium poppy (Papaver somniferum) which originates in western Europe; the sycamore tree (Ficus sycomorus), whose fruits are known to be cultivated in the eastern Mediterranean, especially Egypt, and whose presence in Israel as a locally grown tree is first attested to in the Iron Age by the presence of its fruit; and finally, cumin (Cuminum cyminum), a spice originating in the Eastern Mediterranean. 

Sue Frumin, a PhD student at Prof. Ehud Weiss's archaeobotanical lab, Bar-Ilan University, explains that "the edible parts of these species - opium poppy, sycamore, and cumin - were not identified in the archaeobotanical record of Israel prior to the Iron Age, when the Philistine culture first appeared in the region. None of these plants grows wild in Israel today, but instead grows only as cultivated plants."

Species turnover between the Bronze and Iron Age at Iron Age sites. Each site is marked by two columns. The green column marks the number of Bronze Age species found in the Iron Age floral list. The red column marks the number of new species in Iron Age sites. Numbers beneath the site name give the absolute numbers of Bronze Age /Iron Age species.
Map produced by M. Frumin using ArcGIS for Desktop (ArcMap 10.1), ESRI.

In addition to the translocation of exotic plants from other regions, the Philistines were the first community to exploit over 70 species of synanthropic plants (species which benefit from living in the vicinity of man) that were locally available in Israel, such as Purslane, Wild Radish, Saltwort, Henbane and Vigna. These plant species were not found in archaeological sites pre-dating the Iron Age, or in Iron Age archaeological sites recognized as belonging to non-Philistine cultures - Canaanite, Israelite, Judahite, and Phoenician. The "agricultural revolution" that accompanied the Philistine culture reflects a different agrarian regime and dietary preferences to that of their contemporaries.

The fact that the three exotic plants introduced by the Philistines originate from different regions accords well with the diverse geographic origin of these people. The Philistines - one of the so called Sea Peoples, and mentioned in the Bible and other ancient sources - were a multi-ethnic community with origins in the Aegean, Turkey, Cyprus and other regions in the Eastern Mediterranean who settled on the southern coastal plain of Israel in the early Iron Age (12th century BCE), and integrated with Canaanite and other local populations, finally to disappear at the end of the Iron Age (ca. 600 BCE).

The results of this research indicate that the ca. 600 year presence of the Philistine culture in Israel had a major and long-term impact on local floral biodiversity. The Philistines left as a biological heritage a variety of plants still cultivated in Israel, including, among others, sycamore, cumin, coriander, bay tree and opium poppy.

The Philistines also left their mark on the local fauna. In a previous study also published inScientific Reports in which two of the present authors (Maeir and Kolska Horwitz) participated, DNA extracted from ancient pig bones from Philistine and non-Philistine sites in Israel demonstrated that European pigs were introduced by the Philistines into Israel and slowly swamped the local pig populations through inter-breeding. As a consequence, modern wild boar in Israel today bears a European haplotype rather than a local, Near Eastern one.

As illustrated by these studies, the examination of the ancient bio-archaeological record has the potential to help us understand the long-term mechanisms and vectors that have contributed to current floral and faunal biodiversity, information that may also assist contemporary ecologists in dealing with the pressing issue of invasive species.



Contacts and sources: 
Elana Oberlander
Bar-Ilan University

Two Black Holes Found in Quasar Nearest Earth


A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope. The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive black holes assemble their masses through violent mergers.

OU astrophysicist and his Chinese collaborator used observations from NASA's Hubble Space Telescope to find two supermassive black holes in Markarian 231.

Credit:  Space Telescope Science Institute, Baltimore, Maryland

Xinyu Dai, professor in the Homer L. Dodge Department of Physics and Astronomy, OU College of Arts and Sciences, collaborated on this project with Youjun Lu of the National Astronomical Observatories of China, Chinese Academy of Sciences. Dai and Lu looked at ultraviolet radiation emitted from the center of the Mrk 231 from Hubble observations, then applied a model developed by Lu to the spectrum of the galaxy. As a result, they were able to predict the existence of the binary black holes in Mrk 231.

"We are extremely excited about this finding because it not only shows the existence of a close binary black hole in Mrk 231, but also paves a new way to systematically search binary black holes via the nature of their ultraviolet light emission," said Lu, National Astronomical Observatories of China, Chinese Academy of Sciences.

"The structure of our universe, such as those giant galaxies and clusters of galaxies, grows by merging smaller systems into larger ones, and binary black holes are natural consequences of these mergers of galaxies," said Dai.

So over time, the two black holes discovered by Dai and Lu in Mrk 231 will collide and merge to form a quasar with a supermassive black hole. A quasar is an active galaxy with an illuminated center, which is short lived compared to the age of the universe.




Contacts and sources:
 Xinyu Dai  
Jana Smith
University of Oklahoma 

The results of this project were published in the August 14, 2015, edition of The Astrophysical Journal

Thursday, August 27, 2015

NASA Finds Vegetation Essential For Limiting City Warming Effects


Cities are well known hot spots - literally. The urban heat island effect has long been observed to raise the temperature of big cities by 1 to 3°C (1.8 to 5.4°F), a rise that is due to the presence of asphalt, concrete, buildings, and other so-called impervious surfaces disrupting the natural cooling effect provided by vegetation. According to a new NASA study that makes the first assessment of urbanization impacts for the entire continental United States, the presence of vegetation is an essential factor in limiting urban heating.

The temperature difference between urban areas and surrounding vegetated land due to the presence of impervious surfaces across the continental United States.

Credits: NASA's Earth Observatory

Impervious surfaces' biggest effect is causing a difference in surface temperature between an urban area and surrounding vegetation. The researchers, who used multiple satellites' observations of urban areas and their surroundings combined into a model, found that averaged over the continental United States, areas covered in part by impervious surfaces, be they downtowns, suburbs, or interstate roads, had a summer temperature 1.9°C higher than surrounding rural areas. In winter, the temperature difference was 1.5 °C higher in urban areas.

"This has nothing to do with greenhouse gas emissions. It's in addition to the greenhouse gas effect. This is the land use component only," said Lahouari Bounoua, research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study.

The study, published this month in Environmental Research Letters, also quantifies how plants within existing urban areas, along roads, in parks and in wooded neighborhoods, for example, regulate the urban heat effect.

"Everybody thinks, 'urban heat island, things heat up.' But it's not as simple as that. The amount and type of vegetation plays a big role in how much the urbanization changes the temperature," said research scientist and co-author Kurtis Thome of Goddard.

The urban heat island effect occurs primarily during the day when urban impervious surfaces absorb more solar radiation than the surrounding vegetated areas, resulting in a few degrees temperature difference. The urban area has also lost the trees and vegetation that naturally cool the air. As a by-product of photosynthesis, leaves release water back into to the atmosphere in a process called evapotranspiration, which cools the local surface temperature the same way that sweat evaporating off a person's skin cools them off. Trees with broad leaves, like those found in many deciduous forests on the East coast, have more pores to exchange water than trees with needles, and so have more of a cooling effect.

Impervious surface and vegetation data from NASA/U.S. Geologic Survey's Landsat 7 Enhanced Thematic Mapper Plus (EMT+) sensor and NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua satellites were combined with NASA's Simple Biosphere model to recreate the interaction between vegetation, urbanization and the atmosphere at five-kilometer resolution and at half-hour time steps across the continental United States for the year 2001. The temperatures associated with urban heat islands range within a couple degrees, even within a city, with temperatures peaking in the central, often tree-free downtown and tapering out over tree-rich neighborhoods often found in the suburbs.

The northeast I-95 corridor, Baltimore-Washington, Atlanta and the I-85 corridor in the southeast, and the major cities and roads of the Midwest and West Coast show the highest urban temperatures relative to their surrounding rural areas. Smaller cities have less pronounced increases in temperature compared to the surrounding areas. In cities like Phoenix built in the desert, the urban area actually has a cooling effect because of irrigated lawns and trees that wouldn't be there without the city.

"Anywhere in the U.S. small cities generate less heat than mega-cities," said Bounoua. The reason is the effect vegetation has on keeping a lid on rising temperatures.

Bounoua and his colleagues used the model environment to simulate what the temperature would be for a city if all the impervious surfaces were replaced with vegetation. Then slowly they began reintroducing the urban impervious surfaces one percentage point at a time, to see how the temperature rose as vegetation decreased and impervious surfaces expanded.

What they found was unexpected. When the impervious surfaces were at one percent the corresponding rise in temperature was about 1.3°C. That temperature difference then held steady at about 1.3°C as impervious surfaces increased to 35 percent. As soon as the urban impervious surfaces surpassed 35 percent of the city's land area, then temperature began increasing as the area of urban surfaces increased, reaching 1.6°C warmer by 65 percent urbanization.

At the human level, a rise of 1°C can raise energy demands for air conditioning in the summer from 5 to 20 percent in the United States, according the Environmental Protection Agency. So even though 0.3°C may seem like a small difference, it still may have impact on energy use, said Bounoua, especially when urban heat island effects are exacerbated by global temperature rises due to climate change.

Understanding the tradeoffs between urban surfaces and vegetation may help city planners in the future mitigate some of the heating effects, said Thome.

"Urbanization is a good thing," said Bounoua. "It brings a lot of people together in a small area. Share the road, share the work, share the building. But we could probably do it a little bit better."



Contacts and sources:
Ellen Gray
NASA Goddard Space Flight Center

3-D Cancer Models Give Fresh Perspective on Progress of Disease


Computer models of developing cancers reveal how tiny movements of cells can quickly transform the makeup of an entire tumour.

The models reinforce laboratory studies of how tumours evolve and spread, and why patients can respond well to therapy, only to relapse later.

This is a three-dimensional model of a tumor showing cell types in varying colors.

Credit: Bartek Waclaw and Martin Nowak

Researchers used mathematical algorithms to create three-dimensional simulations of cancers developing over time. They studied how tumours begin with one rogue cell which multiplies to become a malignant mass containing many billions of cells.

Their models took into account changes that occur in cancerous cells as they move within the landscape of a tumour, and as they replicate or die. They also considered genetic variation, which makes some cells more suited to the environment of a tumour than others.

They found that movement and turnover of cells in a tumour allows those that are well suited to the environment to flourish. Any one of these can take over an existing tumour, replacing the original mass with new cells quickly - often within several months.

This helps explain why tumours are comprised mostly of one type of cell, whereas healthy tissue tends to be made up of a mixture of cell types.

However, this mechanism does not entirely mix the cells inside the tumour, the team say. This can lead to parts of the tumour becoming immune to certain drugs, which enables them to resist chemotherapy treatment. Those cells that are not killed off by treatment can quickly flourish and repopulate the tumour as it regrows. Researchers say treatments that target small movements of cancerous cells could help to slow progress of the disease.

The study, a collaboration between the University of Edinburgh, Harvard University and Johns Hopkins University, is published in the journal Nature. The research was supported by the Leverhulme Trust and The Royal Society of Edinburgh.

Dr Bartlomiej Waclaw, of the University of Edinburgh's School of Physics and Astronomy, who is the lead author of the study, said: "Computer modelling of cancer enables us to gain valuable insight into how this complex disease develops over time and in three dimensions."


Contacts and sources:
Catriona Kelly
University of Edinburgh

'Brainbow' Reveals Surprising Data about Visual Connections in Brain

Neuroscientists know that some connections in the brain are pruned through neural development. Function gives rise to structure, according to the textbooks. But scientists at the Virginia Tech Carilion Research Institute have discovered that the textbooks might be wrong.

Their results were published today in Cell Reports.

"Retinal neurons associated with vision generate connections in the brain, and as the brain develops it strengthens and maintains some of those connections more than others. The disused connections are eliminated," said Michael Fox, an associate professor at the Virginia Tech Carilion Research Institute who led the study. "We found that this activity-dependent pruning might not be as simple as we'd like to believe."

Fox and his team of researchers used two different techniques to examine how retinal ganglion cells - neurons that live in the retina and transmit visual information to the visual centers in the brain - develop in a mouse model.

"It's widely accepted that synaptic connections from about 20 retinal ganglion cells converge onto cells in the lateral geniculate nucleus during development, but that number reduces to just one or two by the third week of a mouse's life," Fox said. "It was thought that the mature retinal ganglion cells develop several synaptic terminals that cluster around information exchange points."

The theory of several terminals blossoming from the same retinal ganglion cell had not been proved, though, so Fox and his researchers decided to follow the terminals to their roots.

Using a technique dubbed "brainbow," the scientists tagged the terminals with proteins that fluoresce different colors. The researchers thought one color, representing the single source of the many terminals, would dominate in the clusters. Instead, several different colors appeared together, intertwined but distinct.''

Using a technique dubbed "brainbow," the Virginia Tech Carilion Research Institute scientists tagged synaptic terminals with proteins that fluoresce different colors. The researchers thought one color, representing the single source of the many terminals, would dominate in the clusters. Instead, several different colors appeared together, intertwined but distinct.

Credit: Virginia Tech

"The samples showed a true 'brainbow,'" said Aboozar Monavarfeshani, a graduate student in Fox's laboratory who tagged the terminals. "I could see, right in front of me, something very different than the concept I learned from my textbooks."

The results showed individual terminals from more than one retinal ganglion cell in a mature mouse brain.

The study is a direct contradiction to some other research indicating neural development weeds out most connections between retinal ganglion axons and target cells in the brain, and Fox and his team have more questions.

"Is this a discrepancy a technical issue with the different types of approaches applied in all of these disparate studies?" Fox asked. "Possibly, but perhaps it's more likely that retinal ganglion cells are more complex than previously thought."

Along with the brainbow technique, Fox's team also imaged these synaptic connections with electron microscopy.

Sarah Hammer, currently a sophomore at Virginia Tech, traced individual retinal terminals through hundreds of serial images.

The data confirmed the results from "brainbow" analysis - retinal axons from numerous retinal ganglion cells remained present on adult brain cells.

"These results are not what we expected, and they will force us to reevaluate our understanding of the architecture and flow of visual information through neural pathways," Fox said. "The dichotomy of these results also sheds important light on the benefits of combining approaches to understand complicated problems in science."

Albert Pan, an assistant professor in the Medical College of Georgia at Georgia Regents University, who is an expert in neural circuitry development, said the results are unexpected.

"The research provides strong evidence for multiple innervation and calls for a reevaluation of the current understanding of information flow and neural circuit maturation in the visual system" said Pan, who was not involved in the study. "The paper probably generates more questions than it answers, which is a hallmark of an exciting research study."

The research continues, as Fox's team works to understand exactly how many retinal terminals converge and how they might convey information differently. Once the scientists understand the intricacies of the brain's visual circuitry, they might be able to start developing therapeutics for when it goes wrong.

"The lesson in this particular study is that no single technique gives us all the right answers," Fox said. "Science is never as simple as we like to make it seem."



Contacts and sources:
Paula Brewer ByronVirginia Tech 

What Would A Tsunami In The Mediterranean Look Like?


A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

This  animation shows water elevation for an earthquake-induced tsunami at the Southwest of Crete.   
Credit: Samaras et al., Ocean Science, 2015

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African plate slides underneath the Eurasian plate. About 10% of all tsunamis worldwide happen in the Mediterranean, with on average, one large tsunami happening in the region once a century. The risk to coastal areas is high because of the high population density in the area - some 130 million people live along the sea's coastline. Moreover, tsunami waves in the Mediterranean need to travel only a very short distance before hitting the coast, reaching it with little advance warning. The new study shows the extent of flooding in selected areas along the coasts of southern Italy and Greece, if hit by large tsunamis in the region, and could help local authorities identify vulnerable areas.

Beaches in southern Crete could be affected by an Eastern Mediterranean tsunami 
Credit: Olaf Tausch

"The main gap in relevant knowledge in tsunami modelling is what happens when tsunami waves approach the nearshore and run inland," says Achilleas Samaras, the lead author of the study and a researcher at the University of Bologna in Italy. The nearshore is the zone where waves transform - becoming steeper and changing their propagation direction - as they propagate over shallow water close to the shore. "We wanted to find out how coastal areas would be affected by tsunamis in a region that is not only the most active in the Mediterranean in terms of seismicity and tectonic movements, but has also experienced numerous tsunami events in the past."

The team developed a computer model to represent how tsunamis in the Mediterranean could form, propagate and hit the coast, using information about the seafloor depth, shoreline and topography. "We simulate tsunami generation by introducing earthquake-generated displacements at either the sea bed or the surface," explains Samaras. "The model then simulates how these disturbances - the tsunami waves - propagate and are transformed as they reach the nearshore and inundate coastal areas."

This  animation shows water elevation for an earthquake-induced tsunami at the East of Sicily. 

Credit: Samaras et al., Ocean Science, 2015

As detailed in the Ocean Science study, the team applied their model to tsunamis generated by earthquakes of approximately M7.0 magnitude off the coasts of eastern Sicily and southern Crete. Results show that, in both cases, the tsunamis would inundate the low-lying coastal areas up to approximately 5 metres above sea level. The effects would be more severe for Crete where some 3.5 square kilometres of land would be under water.

"Due to the complexity of the studied phenomena, one should not arbitrarily extend the validity of the presented results by assuming that a tsunami with a magnitude at generation five times larger, for example, would result in an inundation area five times larger," cautions Samaras. "It is reasonable, however, to consider such results as indicative of how different areas in each region would be affected by larger events."

"Although the simulated earthquake-induced tsunamis are not small, there has been a recorded history of significantly larger events, in terms of earthquake magnitude and mainshock areas, taking place in the region," says Samaras. For example, a clustering of earthquakes, the largest with magnitude between 8.0 and 8.5, hit off the coast of Crete in 365 AD. The resulting tsunami destroyed ancient cities in Greece, Italy and Egypt, killing some 5000 people in Alexandria alone. More recently, an earthquake of magnitude of about 7.0 hit the Messina region in Italy in 1908, causing a tsunami that killed thousands, with observed waves locally exceeding 10 metres in height.

The team sees the results as a starting point for a more detailed assessment of coastal flooding risk and mitigation along the coasts of the Eastern Mediterranean. "Our simulations could be used to help public authorities and policy makers create a comprehensive database of tsunami scenarios in the Mediterranean, identify vulnerable coastal regions for each scenario, and properly plan their defence."



Contacts and sources:
Barbara Ferreira
European Geoscience Union

Citation: Samaras, A. G., Karambas, Th. V., and Archetti, R.: Simulation of tsunami generation, propagation and coastal inundation in the Eastern Mediterranean, Ocean Sci., 11, 643-655, doi:10.5194/os-11-643-2015, 2015.