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Sunday, September 30, 2012

Fish Getting Smaller As The Oceans Warm: UBC Research

Changes in ocean and climate systems could lead to smaller fish, according to a new study led by fisheries scientists at the University of British Columbia.

The study, published today in the journal Nature Climate Change, provides the first-ever global projection of the potential reduction in the maximum size of fish in a warmer and less-oxygenated ocean.

These goldband fusiliers are schooling because their swimming is synchronized
File:School of Pterocaesio chrysozona in Papua New Guinea 1.jpg
Credit: Wikipedia

The researchers used computer modeling to study more than 600 species of fish from oceans around the world and found that the maximum body weight they can reach could decline by 14-20 per cent between years 2000 and 2050, with the tropics being one of the most impacted regions.

"We were surprised to see such a large decrease in fish size," says the study's lead author William Cheung, an assistant professor at the UBC Fisheries Centre. "Marine fish are generally known to respond to climate change through changing distribution and seasonality. But the unexpectedly big effect that climate change could have on body size suggests that we may be missing a big piece of the puzzle of understanding climate change effects in the ocean."

This is the first global-scale application of the idea that fish growth is limited by oxygen supply, which was pioneered more than 30 years ago by Daniel Pauly, principal investigator with UBC's Sea Around Us Project and the study's co-author.

"It's a constant challenge for fish to get enough oxygen from water to grow, and the situation gets worse as fish get bigger," explains Pauly. "A warmer and less-oxygenated ocean, as predicted under climate change, would make it more difficult for bigger fish to get enough oxygen, which means they will stop growing sooner."

This study highlights the need to curb greenhouse gas emissions and develop strategies to monitor and adapt to changes that we are already seeing, or we risk disruption of fisheries, food security and the way ocean ecosystems work.

View of different fish species from a tunnel aquarium
File:Tunnelaquarium 14-05-2009 15-54-09.JPG

Credit: Wikipedia


Contacts and sources:
William Cheung
University of British Columbia

Vitamin D Deficiency Increases Risk Of Heart Disease

New research from the University of Copenhagen and Copenhagen University Hospital shows that low levels of vitamin D are associated with a markedly higher risk of heart attack and early death. The study involved more than 10,000 Danes and has been published in the well-reputed American journal Arteriosclerosis, Thrombosis and Vascular Biology.

Vitamin D deficiency has traditionally been linked with poor bone health. However, the results from several population studies indicate that a low level of this important vitamin may also be linked to a higher risk of ischemic heart disease, a designation that covers heart attack, coronary arteriosclerosis and angina. Other studies show that vitamin D deficiency may increase blood pressure, and it is well known that high blood pressure increases the risk of heart attack.

Credit: University of Copenhagen

"We have now examined the association between a low level of vitamin D and ischemic heart disease and death in the largest study to date. We observed that low levels of vitamin D compared to optimal levels are linked to 40% higher risk of ischemic heart disease, 64% higher risk of heart attack, 57% higher risk of early death, and to no less than 81% higher risk of death from heart disease," says Dr. Peter Brøndum-Jacobsen, Clinical Biochemical Department, Copenhagen University Hospital.

The scientists have compared the 5% lowest levels of vitamin D (less than 15 nanomol vitamin per litre serum) with the 50% highest levels (more than 50 nanomol vitamin per litre serum). In Denmark, it is currently recommended to have a vitamin D status of at least 50 nanomol vitamin per litre serum.

The higher risks are visible, even after adjustment for several factors that can influence the level of vitamin D and the risk of disease and death. This is one of the methods scientists use to avoid bias.
Blood samples from more than 10,000 Danes

The population study that forms the basis for this scientific investigation is the Copenhagen City Heart Study, where levels of vitamin D were measured in blood samples from 1981-1983. Participants were then followed in the nationwide Danish registries up to the present.

Credit: University of Copenhagen

"With this type of population study, we are unable to say anything definitive about a possible causal relationship. But we can ascertain that there is a strong statistical correlation between a low level of vitamin D and high risk of heart disease and early death. The explanation may be that a low level of vitamin D directly leads to heart disease and death. However, it is also possible that vitamin deficiency is a marker for poor health generally," says Børge Nordestgaard, clinical professor at the Faculty of Health and Medical Sciences, University of Copenhagen and senior physician at Copenhagen University Hospital.

Long-term goal is prevention

The scientists are now working to determine whether the connection between a low level of vitamin D and the risk of heart disease is a genuine causal relationship.

If this is the case, it will potentially have a massive influence on the health of the world population. Heart disease is the most common cause of adult death in the world according to the World Health Organization (WHO), which estimates that at least 17 million people die every year from heart disease.

"The cheapest and easiest way to get enough vitamin D is to let the sun shine on your skin at regular intervals. There is plenty of evidence that sunshine is good, but it is also important to avoid getting sunburned, which increases the risk of skin cancer. Diet with a good supply of vitamin D is also good, but it has not been proven that vitamin D as a dietary supplement prevents heart disease and death," says Børge Nordestgaard.

Vitamin D Facts 

The average person gets 1/5 of his or her need for vitamin D covered through diet and 4/5 through sunlight.

Vitamin D is produced in the skin. The amount of sunlight needed to cover the body’s requirement for vitamin D corresponds to 5-30 minutes of sunlight on arms, neck and head several times a week in spring, summer and early fall in most countries. However, in late fall and winter in Northen countires/states and in countries closer to the South Pole, the sun is so low in the sky that it does not provide enough light to initiate vitamin D production in the skin. Therefore, in such countries diet and possibly vitamin D supplements are extremely important as sources of vitamin D in the winter half of the year.

National health authories often recommend on intake of vitamin D. For example, the Danish Health and Medicines Authority recommends a daily consumption of 7.5 µg of vitamin D. Most Danes receive from 2-4 µg of vitamin D from diet. With the exception of certain mushrooms, only animal products contain vitamin D (fish, meat, eggs and dairy products). In Denmark, it is recommended to eat 200-300 g of fish every week. Fatty fish in particular is rich in vitamin D.

Vitamin D is important for good bone health, and vitamin D deficiency is a risk factor for the development of osteoporosis. Whether vitamin D can have a protective effect on the development of heart disease and certain types of cancer is not yet known, which is why recommendations for vitamin D supplementation are aimed primarily at preventing osteoporosis. Supplements are most often not recommended for healthy individuals who eat a varied diet.

However, vitamin D supplementation is often recommended for pregnant women, children under the age of two, people with dark skin, women who are veiled in the summer half of the year and for people over the age of 70.


Contacts and sources: 
Professor Børge Nordestgaard
Faculty of Health and Medical Sciences
Copehagen University Hospital

Gut Bacteria Could Cause Diabetes

 Gut Bacteria and Type 2 Diabetes

Studying gut bacteria can reveal a range of human illness. Now, new research shows that the composition of a person’s intestinal bacteria could play an important role in the development of type 2 diabetes. These results, from a joint European and Chinese research team, have just been published in the journal Nature.

The number of people suffering from type 2 diabetes world-wide has risen rapidly in recent years, and scientists estimate that just as many people could be suffering from the illness without realising it. New research now indicates that your gut bacteria can reveal whether you suffer from the disease.

“We have demonstrated that people with type 2 diabetes have a high level of pathogens in their intestines,” says Jun Wang, Executive Director of BGI and professor from theUniversity of Copenhagen’s Department of Biology and Novo Nordisk Foundation Center for Basic Metabolic Research.


Credit: University of Copenhagen.

See video where professor Jun Wang and professor Oluf Borbye Pedersen explain the results just published in the scientific journal Nature.
Important intestinal bacteria

The 1.5 kilograms of bacteria that we each carry in our intestines have an enormous impact on our health and well being. The bacteria normally live in a sensitive equilibrium but if this equilibrium is disrupted our health could suffer. In the new study, scientists examined the intestinal bacteria of 345 people from China, of which 171 had type 2 diabetes. The team managed to identify clear biological indicators that someday could be used in methods that provide faster and earlier diagnosis of type 2 diabetes.

The research, which was recently published in the scientific journal Nature, also demonstrated that people with type 2 diabetes have a more hostile bacterial environment in their intestines, which can increase resistance to different medicines.

Similar studies carried out on sufferers of type 2 diabetes in Denmark also discovered a significant imbalance in the function of their intestinal bacteria and composition. Future Danish studies will examine whether intestinal bacteria is already abnormal in people that are deemed to be at risk of developing diabetes.

File:Main symptoms of diabetes.png
Credit: Wikipedia

“We are going to transplant gut bacteria from people that suffer from type 2 diabetes into mice and examine whether the mice then develop diabetes,” says another of the lead scientists behind the project, professor Oluf Borbye Pedersen from the University of Copenhagen and centre director at LuCamp, the Lundbeck Foundation Centre for Applied Medical Genomics in Personalised Disease Prediction, Prevention and Care.

International research team investigates gut bacteria

By working together, a team scientists from the University of Copenhagen and theBeijing Genomics Institute (BGI) was able to make to several breakthroughs in the field of ‘metagenomics’.

Scientists working on the EU research project MetaHIT have uncovered more than 3.3 million genes from gut bacteria found in people from Spain and Denmark. These genes could play a key role in understanding and treating a range of serious illnesses. According to Professor Karsten Kristiansen from the University of Copenhagen’s Department of Biology, the recent discovery is an important step in the comprehensive international research that is currently underway to investigate the interplay between intestinal bacteria and health.

“The European and Chinese working on the MetaHIT project were able to make important new discoveries about the relationship between intestinal bacteria and health. The new discovery indicates a possible connection between type 2 diabetes and the intestinal bacteria in Chinese people,” Kristiansen says.

“It is important to point out that our discovery demonstrates a correlation. The big question now is whether the changes in gut bacteria can affect the development of type 2 diabetes or whether the changes simply reflect that the person is suffering from type 2 diabetes.”

Contact and sources:
Professor Karsten Kristiansen
Professor Oluf Borbye Pedersen
Communications Officer Helle Blæsild 
University of Copenhagen.

Ancient Stinging Nettles Reveal Bronze Age Trade Connections

A piece of nettle cloth retrieved from Denmark's richest known Bronze Age burial mound Lusehøj may actually derive from Austria, new findings suggest. The cloth thus tells a surprising story about long-distance Bronze Age trade connections around 800 BC. The findings have just been published in Nature's online journal Scientific Reports.

  This shows the remains of the nettle cloth.
Credit:  The National Museum of Denmark

2,800 years ago, one of Denmark's richest and most powerful men died. His body was burned. And the bereaved wrapped his bones in a cloth made from stinging nettle and put them in a stately bronze container, which also functioned as urn.

Now new findings suggest that the man's voyage to his final resting place may have been longer than such voyages usually were during the Bronze Age: the nettle cloth, which was wrapped around the deceased's bones, was not made in Denmark, and the evidence points to present-day Austria as the place of origin. 

Karin Margarita Frei analyses the nettles.
 
Credit: National Museum of Denmark.

"I expected the nettles to have grown in Danish soil on the island of Funen, but when I analysed the plant fibres' strontium isotope levels, I could see that this was not the case," explains postdoc Karin Margarita Frei from the Danish National Research Foundation's Centre for Textile Research at the University of Copenhagen.

"The levels indicate that the nettles grew in an area with geologically old bedrock. We can only find rock with similar levels of strontium isotope in Sweden and Norway as well as in Central Europe."

Karin Margarita Frei had to conclude that Bronze Age Danes did not use local stinging nettle for their nettle textiles.

Strontium tells us where we come from

It is Karin Margarita Frei who has developed the method to determine plant textiles' strontium isotope levels that has led to the surprising discovery.

Strontium is an element which exists in the earth's crust, but its prevalence is subject to geological and topographical variation. Humans, animals, and plants absorb strontium through water and food. By measuring the strontium level in archaeological remains, researchers can determine where humans and animals lived, and where plants grew.

The new discovery is the result of a collaboration between an international team of researchers from the Danish National Research Foundation's Centre for Textile Research at the University of Copenhagen, the University of Bergen in Norway, and the National Museum of Denmark. The findings are described in an article that has just been published in Nature's online journalScientific Reports.

Made in Austria
Karin Margarita Frei's work and the grave's archaeological remains suggest that the cloth may have been produced as far away as the Alps.

The bronze container, which has been used as urn, is of Central European origin and probably from the Kärnten-Steiermark region in Austria. The strontium isotope analysis of the cloth indicates that it may very well be from the same region. This assumption is supported by yet incomplete analyses of pitch found in the Lusehøj grave.

Textile archaeologist Ulla Mannering from the National Museum of Denmark offers an explanation as to how an Austrian cloth ended up in Funen, Denmark.

"Bronze Age Danes got their bronze from Central Europe, and imports were controlled by rich and powerful men. We can imagine how a bronze importer from Funen in Denmark died on a business trip to Austria. His bones were wrapped in an Austrian nettle cloth and placed in a stately urn that his travel companions transported back to Denmark," Ulla Mannering suggests.

Nettles made good textile

The strontium isotope analyses have surprised Ulla Mannering.

She concludes on the basis of the analyses that Central Europeans still used wild plants for textile production during the Bronze Age while at the same time cultivating textile plants such as flax on a large scale. Nettle textiles could apparently compete with textiles made from flax and other materials because top quality nettle fabrics are as good as raw silk.

The strontium isotope analysis also mean that Danish textile history needs revision.

"Until recently the Lusehøj nettle cloth was the oldest nettle cloth we knew, and the only Bronze Age nettle cloth, but with our new findings we actually have no evidence that nettle textiles were produced in Denmark at all during the Bronze Age," Ulla Mannering points out.

The new research is achieved by collaboration between an international team of researchers from the Centre for Textile Research University of Copenhagen , National Museum and the University of Bergen. They are published in an article that has just been published in the renowned journal Nature online magazine, Scientific Reports .

Karin Margarita Frei results and archaeological objects from the tomb suggest that the cloth can be made as far away as the Alps.

Bronze vessel from Lusehøj
Credit: National Museum of Denmark.

Bronze vessel, which is used as the urn is produced in Central Europe, most likely in Carinthia, Styria in Austria. Based on strontiumisotopanalyse can nældeklædet well also come from there. This assumption is supported by several unfinished analysis including some pitch from the grave in Lusehøj.

Textile archaeologist Ulla Mannering from the National Museum has a vision of how an Austrian cloth ended up on Funen.

Bronze Age Danes got their bronze from Central Europe. Imports were driven by some rich, powerful men in the top. We can imagine that a Fyn bronze importer died during a trade trip in Austria. His charred bones were wrapped in an Austrian nældeklæde and placed in an appropriate fine urn, as his traveling companions transported back to Funen, says Ulla Mannering.
Nettles was good substance

She concluded that in the Bronze Age Central Europe people still used wild plants for textile manufacturing, while others used large-scale cultivated textile plants such as flax. Nettle fabric was apparently competitive with fabrics of flax, and the its best quality conjures a comparison with  raw silk. 

The strontium isotope analyses also mean that Danish textile history needs revision.

“Until recently the Lusehøj nettle cloth was the oldest nettle cloth we knew, and the only Bronze Age nettle cloth, but with our new findings we actually have no evidence that nettle textiles were produced in Denmark at all during the Bronze Age,”  says Mannering.

 Lusehøj burial moundLusehøj
Credit: Torben Dehn

According to writer Karsten Kjer Michaelsen  is a truly royal burial mound. It was excavated and investigated in 1861 at the request of King Frederik VII, who was interested in archaeology. The treasure and symbols of the past discovered made quite a stir and added extra sparkle to the King's archaeological collection. But the excavation was heavy handed and incomplete. A new investigation was therefore initiated in 1973-75. The archaeologists found artifacts including broken wine bottles from the King's excavation a good century before. Lusehøj was also confirmed as the final resting place of a uniquely wealthy chieftain. The name Lusehøj is  based on the Danish word "lys" meaning light. "


Earth To Be Bombarded By Orionid Meteor Shower, October Events In The Night Sky And Where To Find Them

Backyard stargazers get a monthly guide to the northern hemisphere's skywatching events with "Tonight's Sky." In October, remnants of Halley's Comet burn up in the Orionid meteor shower.

"Tonight's Sky" is produced by HubbleSite.org, online home of the Hubble Space Telescope. This is a recurring show, and you can find more episodes — and other astronomy videos — at HubbleSite.org.

Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is being used in planetarium projectors. Just set your coordinates and go. http://www.stellarium.org/  You can use it to identify the sky in your neighborhood no matter where you live.  

Highlights of the October Sky

Evening Planets: 
Mars dips toward the southwestern horizon in the early evenings of October. It slips even closer to the horizon, and gets even harder to spot, later in the month.

Jupiter rises in the late evening to dominate the sky throughout the rest of the night. Use binoculars or a small telescope to admire the giant planet’s features.

Constellations and Deep-Sky Objects
Pegasus, the great winged horse of Greek mythology, prances across the autumn night sky. His body is denoted by a large area of stars known as the “Great Square.” Coordinates: Right Ascension: 22h Declination: +20º
Pegasus Constellation
Johannes Hevelius' Pegasus fromUranographia(1690)


The story behind the name: Pegasus, the winged horse, was the son of Poseidon and Medusa. Medusa had been one of three beautiful sisters. Athena was angered that Medusa met with Poseidon in one of her temples. She changed Medusa into a terrible monster. Zeus kept Pegasus out of the world to placate Athena. Pegasus (and the warrior Chrysaor) sprang from Medusa's body after she was killed by Perseus.

Pegasus had been living on Mount Helicon, tended by the Muses for whom he created a drinking well. Bellerophon, a young man accused of murder, fled his city and took refuge with Proteus, the king of Tiryns. Proteus suspected Bellerophon of trying to seduce his wife (not true) and sent him to his father-in-law, King Iobates, with a sealed note repeating the story. Iobates decided to set Bellerophon so difficult a task that he would would not return alive. He asked him to destroy the Chimaera, a fire-breathing monster with a lion's head, a goat's body, and a serpent's tail. Bellerophon consulted a seer who advised him to catch and tame Pegasus. Some versions of the story say that the gods helped him, but in any case, Bellerophon caught and tamed Pegasus. He overcame the Chimera by flying above her and shooting her with arrows, and then forcing a lump of lead down her throat which melted from her fiery breath and burned her insides.

Pegasus hosts 51-Pegasi, the first Sun-like star known to have an extra-solar planet. The brightest corner of the Great Square, Alpheratz, is also the brightest star in the constellation Andromeda. In Greek mythology, this princess was chained to a rock near the sea to appease a sea monster.
 
51 Pegasi: A New Planet Discovered in 1995

 Are we alone  in the universe? Do other stars have planets too? Humanity took one step closer to answering these questions in October 1995 when it was announced that the star 51 Pegasi  harbors at least one planet. In the above picture of 51 Peg  the planet is not visible - it can only be detected by noticing small changes in the star's motion. Claims of planets  orbiting other stars  are rare, with perhaps the most credible pertaining to a neutron star - a star much different than the Sun. But new ground was broken in 1995 when the planetary detection claimed around the normal Sun-like star 51 Peg was confirmed. The planet, discovered by Michel Mayor and Didier Queloz, is thought to be like Jupiter - except orbiting so close to the parent star that it's year lasts only about 4 days! In the above picture the lines centered on 51 Peg are caused by the telescope itself and are not related to the star or planet.

Within Andromeda’s boundaries, look for M31, the Andromeda Galaxy, an island of billions of stars. On a clear, dark night it appears as a faint smudge of light. Approximately 2.5 million light-years away, M31 is the closest spiral galaxy to our own Milky Way Galaxy and the most distant object you can see with your eyes alone. Binoculars and small telescopes reveal M31’s glowing nucleus and spiral arms.

Credit: NASA

A smaller companion galaxy, M110, appears as a faint spot near the large galaxy. The Andromeda Galaxy is slowly pulling in, and will eventually consume, another one of its small companion galaxies, M32.

M110: Satellite of the Andromeda Galaxy 
See Explanation.  Clicking on the picture will download
 the highest resolution version available.
Credit & Copyright : Jean-Charles Cuillandre (CFHT ) & Giovanni Anselmi (Coelum Astronomia ), Hawaiian Starlight

 Our Milky Way Galaxy is not alone. It is part of a gathering of about 25 galaxies known as the Local Group . Members include the Great Andromeda Galaxy (M31), M32M33, the Large Magellanic Cloud, the Small Magellanic CloudDwingeloo 1, several small irregular galaxies , and many dwarf elliptical  and dwarf spheroidal galaxies Pictured on the lower right is one of the dwarf ellipticals NGC 205 . Like M32 NGC 205  is a companion to the large M31, and can sometimes be seen to the south of M31 's center in photographs. The image shows NGC 205 to be unusual for an elliptical galaxy in that it contains at least two dust clouds (at 9 and 2 o'clock - they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier's original catalog.

Morning Planets

Before sunrise, look for Venus blazing brilliantly above the eastern horizon.
 
This global view of the surface of Venus is centered at 180 degrees east longitude.Image credit: NASA/JPL
 
Events
An interesting meteor shower peaks on the night of October 21st to 22nd.  After midnight, look to the east, where the constellation Orion is rising. Every few minutes you may spy a tiny remnant of Halley’s Comet burning up high in the atmosphere. This is the Orionid meteor shower.
 
The night sky is always a celestial showcase. Explore its wonders from your own backyard.

Video Credits
Produced by the Space Telescope Science Institute, Office of Public Outreach 
Starfield images created with Stellarium

Mythological constellation forms from Firmamentum Sobiescianum sive Uranographia by Johannes Hevelius, courtesy of the United States Naval Observatory

Mars image courtesy of Matt Wedel

Jupiter image courtesy of Todd Gross

Andromeda Galaxy (M31) image based on an image courtesy of Naoyuki Kurita

Venus image courtesy of Mario Weigand

Narrated by Nancy Calo

Music written by Jonn Serrie

Production: Lucy Albert, Greg Bacon, John Bintz, John Godfrey, and Vanessa
Thomas


Visit Tonight's Sky on HubbleSite. http://hubblesite.org/explore_astronomy/tonights_sky

Mind Blowing! Plants That Flee Predators Just Discovered


First observation of predator avoidance behavior by phytoplankton

 Scientists at the University of Rhode Island's Graduate School of Oceanography have made the first observation of a predator avoidance behavior by a species of phytoplankton, a microscopic marine plant. Susanne Menden-Deuer, associate professor of oceanography, and doctoral student Elizabeth Harvey made the unexpected observation while studying the interactions between phytoplankton and zooplankton.

Significant modulation of phytoplankton swimming speed and vertical velocity was observed by Menden-Deuer and her colleagues when H. akashiwo was exposed to the actively grazing predator, Favella sp. They observed predator-induced defense behaviors previously unknown for phytoplankton. Modulation of individual phytoplankton movements during and after predator exposure resulted in an effective separation of predator and prey species. The strongest avoidance behaviors were observed when H. akashiwo co-occurred with an actively grazing predator. Predator-induced changes in phytoplankton movements resulted in a reduction in encounter rate and a 3-fold increase in net algal population growth rate.

Heterosigma akashiwo
  File:CCMP452.jpg
Credit: Wikipedia

Their discovery will be published in the September 28 issue of the journal PLOS ONE.

"It has been well observed that phytoplankton can control their movements in the water and move toward light and nutrients," Menden-Deuer said. "What hasn't been known is that they respond to predators by swimming away from them. We don't know of any other plants that do this."

While imaging 3-dimensional predator-prey interactions, the researchers noted that the phytoplankton Heterosigma akashiwo swam differently in the presence of predators, and groups of them shifted their distribution away from the predators.

 Favella sp.

Credit: w3.ualg.pt

In a series of laboratory experiments, Menden-Deuer and Harvey found that the phytoplankton not only flee when in the presence of the predatory zooplankton, but they also flee when in water that had previously contained the predators. They found only a minimal effect when the phytoplankton were exposed to predators that do not feed on phytoplankton.

"The phytoplankton can clearly sense the predator is there. They flee even from the chemical scent of the predator but are most agitated when sensing a feeding predator," said Menden-Deuer.

When the scientists provided the phytoplankton with a refuge to avoid the predator – an area of low salinity water that the predators cannot tolerate – the phytoplankton moved to the refuge.

The important question these observations raise, according to Menden-Deuer, is how these interactions affect the survival of the prey species.

Measuring survival in the same experiments, the researchers found that fleeing helps the alga survive. Given a chance, the predators will eat all of the phytoplankton in one day if the algae have no safe place in which to escape, but they double every 48 hours if they have a refuge available to flee from predators. Fleeing makes the difference between life and death for this species, said Menden-Deuer.

"One of the puzzling things about some phytoplankton blooms is that they suddenly appear," she said. "Growth and nutrient availability don't always explain the formation of blooms. Our observation of algal fleeing from predators is another mechanism for how blooms could form. Amazingly, looking at individual microscopic behaviors can help to explain a macroscopic phenomenon."

The researchers say there is no way of knowing how common this behavior is or how many other species of phytoplankton also flee from predators, since this is the first observation of such a behavior.

"If it is common among phytoplankton, then it would be a very important process," Menden-Deuer said. "I wouldn't be surprised if other species had that capacity. It would be very beneficial to them."

In future studies, she hopes to observe these behaviors in the ocean and couple it with genetic investigations.

Funding for this research was provided by the National Science Foundation, the National Oceanic and Atmospheric Administration, and the U.S. Department of Agriculture. The study was conducted, in part, at the URI Marine Life Science Facility, which is supported by the Rhode Island Experimental Program to Stimulate Competitive Research.


Contacts and sources:
'Todd McLeish
University of Rhode Island

Saturday, September 29, 2012

Microbial Bebop: Listen To The Music Of Undersea Microbes

Soft horns and a tinkling piano form the backbone of “Fifty Degrees North, Four Degrees West,” a jazz number with two interesting twists: it has no composer and no actual musicians. Unless you count bacteria and other tiny microbes, that is.

The song is the brainchild of Peter Larsen, a biologist at the U.S. Department of Energy’s Argonne National Laboratory. Larsen, it turns out, has no musical training at all; his interests run less towards the blues and more towards blue-green algae.

When faced with an avalanche of microbial data collected from samples taken from the western English Channel, Larsen recognized he needed a way to make sense of it all. “Thinking of interesting ways to highlight interactions within data is part of my daily job,” he said. “I am always trying to find new ways to visualize those relationships in ways so that someone can make relevant biological conclusions.”

Like in many musical compositions, seasonal patterns of microbial communities frequently follow variations on a repeating pattern. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated a method by which patterns of taxonomic and environmental parameter data from microbial ecology are translated into music.

Microbial Bebop
Listen to examples of microbial bebop here » or click a tune below.

Blues for Elle: This composition highlights seasonal patterns in marine physical parameters at the L4 Station. The chords are generated from seasonal changes in photosynthetically active radiation. The melody of each measure is comprised of eight notes, each mapped to a physical environmental parameter, in the following order: temperature, soluble reactive phosphate, nitrate, nitrite, saline, silicate, and chlorophyll A concentrations.

Bloom: Some marine microbial taxa are most often present in the L4 Station community at very low abundance, but occasionally become highly dominant community members. To link these microbial blooms to relevant physical parameters, the chords in this composition are derived from changes in chlorophyll A concentrations and salinity. The melody for each measure is derived from the relative abundances of typically rare taxa that were observed to occasionally bloom to higher abundance in the following order: Cyanobacteria, Vibrionales, Opitulates, Pseudomondales, Rhizobiales, Bacillales, Oceanospirallales, and Sphingomonadales.

Cyanobacteria
File:20100422 235222 Cyanobacteria.jpg
Credit: Wikipedia 

Far and Wide: Microbial species of the Order Rickettsiales, such as the highly abundant, free-living planktonic species Pelagibacter ubique, are typically, highly abundant taxa in L4 Station data. Its relative abundance in the microbial community at L4 Station follows a distinctive seasonal pattern. In this composition, there are two chords per measure, generated from photosynthetically active radiation measurements and temperature. The melody of each measure is six notes that describe the relative abundance of the Order Rickettsiales. The first note of each measure is from the relative abundance at a time point. The next five notes of a measure follow one of the following patterns: a continuous rise in pitch, a continuous drop in pitch, a rise then drop in pitch, or a drop then rise in pitch. These patterns are matched to the relative abundance of Rickettsiales at the given time point, relative to the previous and subsequent time points. The pattern of notes in a measure is mapped to the relative abundance of Rickettsiales with fewer rests per measure indicating higher abundance. For time points at which Rickettsiales was the most abundant microbial taxa, the corresponding measure is highlighted with a cymbal crash.

Fifty Degrees North, Four Degrees West: All of the data in this composition derives from twelve observed time points collected at monthly intervals at the L4 Station during 2007. The composition is composed of seven choruses. Each chorus has the same chord progression of 12 measures each in which chords are derived from monthly measures of temperature and chlorophyll A concentrations. The first and last chorus melodies are environmental parameter data as in ‘Blues for Elle’. The melody in each of the second through sixth chorus is generated from the relative abundances of one of the five most common microbial taxa: Rickettsiales, Rhodobacteriales, Flavobacteriales, Cyanobactera, and Pseudomondales. A different ‘instrument’ is used to represent each microbial taxon. Melodies for microbial taxa were generated as in ‘Far and Wide’.

In the case of the western English Channel data, however, Larsen decided that a visual representation of the data would not be as effective as one he could hear.

“There are certain parameters like sunlight, temperature or the concentration of phosphorus in the water that give a kind of structure to the data and determine the microbial populations,” he said. “This structure provides us with an intuitive way to use music to describe a wide range of natural phenomena.”

A colleague of Larsen’s suggested that classical music could effectively represent the data, but Larsen wanted any patterns inherent in the information to emerge naturally and not to be imposed from without.

“For something as structured as classical music, there’s an insufficient amount of structure that you can infer without having to tweak the result to fit what you perceive it should sound like,” Larsen said. “We didn’t want to do that.”

While this is not the first attempt to “sonify” data, it is one of the more mellifluous examples of the genre. “We were astounded by just how musical it sounded,” Larsen said. “A large majority of attempts to converting linear data into sound succeed, but they really don’t obey the dictates of music – meter, tempo, harmony. To see these things in natural phenomena and to describe them was a wonderful surprise.”

According to Larsen, the musicality of the data is not limited to the organisms in the English Channel. In another set of analysis, he and his colleagues used a similar methodology to look at the relationship between a plant and a fungus.

“We expect to see the same intuitive patterns recurring in different environments,” he said. “Sometimes, it can sound a little avant-garde, but it’s not random because it reflects very real phenomena.”

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed byUChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.


Contacts and sources:
Jared Sagoff
DOE/Argonne National Laboratory

A Glowing Future: Nanoparticles Glow Through Thick Layer of Tissue

An international research team has created unique photoluminescent nanoparticles that shine clearly through more than 3 centimeters of biological tissue -- a depth that makes them a promising tool for deep-tissue optical bioimaging.

Though optical imaging is a robust and inexpensive technique commonly used in biomedical applications, current technologies lack the ability to look deep into tissue, the researchers said.

A transmission electron microscopy image of nanoparticles designed for deep-tissue imaging. Each particle consists of a core encased inside a square, calcium-fluoride shell. 
Photo credit: Zhipeng

This creates a demand for the development of new approaches that provide high-resolution, high-contrast optical bioimaging that doctors and scientists could use to identify tumors or other anomalies deep beneath the skin.

The newly created nanoparticles consist of a nanocrystalline core containing thulium, sodium, ytterbium and fluorine, all encased inside a square, calcium-fluoride shell.

The particles are special for several reasons. First, they absorb and emit near-infrared light, with the emitted light having a much shorter wavelength than the absorbed light. This is different from how molecules in biological tissues absorb and emit light, which means that scientists can use the particles to obtain deeper, higher-contrast imaging than traditional fluorescence-based techniques.

Second, the material for the nanoparticles' shell --calcium fluoride -- is a substance found in bone and tooth mineral. This makes the particles compatible with human biology, reducing the risk of adverse effects. The shell is also found to significantly increase the photoluminescence efficiency.

To emit light, the particles employ a process called near-infrared-to-near-infrared up-conversion, or "NIR-to-NIR." Through this process, the particles absorb pairs of photons and combine these into single, higher-energy photons that are then emitted.

One reason NIR-to-NIR is ideal for optical imaging is that the particles absorb and emit light in the near-infrared region of the electromagnetic spectrum, which helps reduce background interference. This region of the spectrum is known as the "window of optical transparency" for biological tissue, since the biological tissue absorbs and scatters light the least in this range.

The scientists tested the particles in experiments that included imaging them injected in mice, and imaging a capsule full of the particles through a slice of pork more than 3 centimeters thick. In each case, the researchers were able to obtain vibrant, high-contrast images of the particles shining through tissue.

The results of the study appeared online on Aug. 28 in the ACS Nano journal. The international collaboration included researchers from the University at Buffalo and other institutions in the U.S., China, South Korea and Sweden. It was co-led by Paras N. Prasad, a SUNY Distinguished Professor and executive director of UB's Institute for Lasers, Photonics and Biophotonics (ILPB), and Gang Han, an assistant professor at University of Massachusetts Medical School.

"We expect that the unprecendented properties in the core/shell nanocrystals we designed will bridge numermous disconnections between in vitro and in vivo studies, and eventully lead to new discoveries in the fields of biology and medicine," said Han, expressing his excitement about the research findings.

Study co-author Tymish Y. Ohulchanskyy, a deputy director of ILPB, believes the 3-centimeter optical imaging depth is unprecedented for nanoparticles that provide such high-contrast visualization.

"Medical imaging is an emerging area, and optical imaging is an important technique in this area," said Ohulchanskyy. "Developing this new nanoplatform is a real step forward for deeper tissue optical bioimaging."

The paper's first authors were Guanying Chen, research assistant professor at ILPB and scientist at China's Harbin Institute of Technology and Sweden's Royal Institute of Technology and Jie Shen of the University of Massachusetts Medical School. Other institutions that contributed included Roswell Park Cancer Institute, the University of North Carolina at Chapel Hill and Korea University at Seoul.

The next step in the research is to explore ways of targeting the nanoparticles to cancer cells and other biological targets that could be imaged. Chen, Shen and Ohulchanskyy said the hope is for the nanoparticles to become a platform for multimodal bioimaging.

Contacts and sources:
Charlotte Hsu
University at Buffalo

Probing The Mysteries Of Cracks And Stresses

Analysis of molecular-level fracture and stress mechanisms could have broad implications for understanding materials' behavior

 Diving into a pool from a few feet up allows you to enter the water smoothly and painlessly, but jumping from a bridge can lead to a fatal impact. The water is the same in each case, so why is the effect of hitting its surface so different?

A dislocation in a crystal lattice, a disconnected region in its structure (represented by the array of atoms shown in blue) can separate from the rest of the lattice at a rate determined by the potential energy of the system, represented by the wavy surface. To the left, the higher potential energy (shown in red) prevents the defect from moving in that direction, but to the lower right (shown in blue) the defect can glide toward a lower-energy state, if it first overcomes the higher-energy hump. Once over that hump, it can move rapidly and continuously — a condition called flow stress. 
Probing the mysteries of cracks and stresses
Image courtesy of Yue Fan and Bilge Yildiz

This seemingly basic question is at the heart of complex research by a team in MIT's Department of Nuclear Science and Engineering (NSE) that studied how materials react to stresses, including impacts. The findings could ultimately help explain phenomena as varied as the breakdown of concrete under sudden stress and the effects of corrosion on various metal surfaces.

Using a combination of computer modeling and experimental tests, the researchers studied one specific type of stress — in a defect called a screw dislocation — in one kind of material, an iron crystal lattice. But the underlying explanation, the researchers say, may have broad implications for many kinds of stresses in many different materials.

The research, carried out by doctoral student Yue Fan, associate professor Bilge Yildiz, and professor emeritus Sidney Yip, is being published this week in the journal Physical Review Letters.

Essentially, the team analyzed how the strength of a material can increase quite abruptly as the rate of strain applied to the material increases. This transition in the rate at which a material cracks or bends, called a flow-stress upturn, has been observed experimentally for many years, but its underlying mechanism has never been fully explained, the researchers say.

"The formulation is not specific to this particular defect," Yildiz explains. Rather, she and her colleagues have figured out what they believe is a set of general principles. "We have proven that it works in this system," she says.

"There are implications that go beyond dislocations, beyond even crystals," Yip adds. But before extending the work — something the team is working on now — the researchers had to prove the principle by applying it to a specific case, in this case the screw dislocation in iron. While other researchers have analyzed behaviors associated with particular kinds of defects in specific materials, with these new general principles, "all of a sudden we have an explanation for their data that does not require such specific assumptions," Yip says.

Flow-stress upturn "is an important phenomenon in materials," Fan says, explaining how they bend and crack in a process called plastic deformation. "It's common in all metals," he says, as well as in many other materials.

But the way that deformation varies, depending on the forces being applied, Fan says, is similar to the way the surface of water in a pool can part gently when a diver hits the surface at a certain rate of speed, but doesn't have time to part and behaves like a solid when the impact is too rapid, as in a jump from a great height.

The key is something called "strain localization," Yip says — that is, the way an impact or other stress is confined to a small initial location, and how rapidly the applied forces can then spread beyond that point. To understand that fully, he says, the team had to analyze how the atoms and molecules move to produce this behavior.

The team found that, in addition to the rate at which the strain is applied, the effect depends critically — and in a highly predictable way — on the temperature of the material. "People think they're independent," Fan says, but it turns out the effects of strain rate and temperature are strongly related.

The effects are quite dramatic, Yildiz says: The rate of change taking place within the material can suddenly change by orders of magnitude, transforming a slow erosion into a sudden catastrophic fracture. The analysis could potentially help predict the breakdown of structures as varied as concrete buildings, metal pressure vessels in powerplants, and the structural components of airplane bodies, but further work will be needed to show how these basic principles can be applied to these different materials.

"I don't want to say it's going to be the exact same phenomenon" in such different cases, Yildiz says, but the underlying principles of coupled environmental factors "could explain significant differences" in the way these materials behave under stress.

"We believe this behavior is universal" among different materials, Yip says, "but we haven't proven that yet. It's the beginning of a long journey."

The work was supported by the U.S. Department of Energy's Consortium for Advanced Simulation of Light Water Reactors and its Division of Materials Sciences and Engineering.


Contacts and sources:
Caroline McCall 
Massachusetts Institute of Technology
Written by David Chandler, MIT News Office

What’s In A Name? Israeli Professor Says People Wrongly Swayed By U.S. President's Middle Name

President Obama’s middle name, Hussein, makes Israelis - both Jewish and Arab - perceive him as less pro-Israeli, reveals a new study conducted by the University of Haifa and the University of Texas. The study has just been published in the journal Political Behavior. “Even though the Israeli public has extensive information about the American President and his positions, their opinions can still be swayed by cultural cues, such as a name that in this case is perceived as Arabic,” says Dr. Israel Waismel-Manor of the University of Haifa who co-authored the study.

barack-obama
Credit: University of Haifa/and the White House

Similar cases in the past have shown that public figures’ names, particularly those carrying cultural significance, can affect how the public perceives their public role. The current study, conducted by Dr. Waismel-Manor and Dr. Natalie Jomini Stroud of the University of Texas, set out to examine if and how Obama’s middle name affects Jewish Israeli, Arab Israeli, and American perceptions, and whether there are differences in how the name affects them due to cultural associations. Participating in the study were Israeli Jewish students; Israeli Arab students; American students who sympathize with Israel; and American students who sympathize with Palestinians.

Each group was asked to watch a 3:40-min. news clip of Obama speaking at an official meeting with Israeli Prime Minister Benjamin Netanyahu and President of the Palestinian Authority Abu Mazen about the peace talks between the sides. A random half of each group was shown the clip with a reference caption that read “President Barack Obama” and the other half saw the clip with the caption “President Barack Hussein Obama”. The caption appeared four times during the clip for a total of 20 seconds. Following the clip, the participants were asked whether Obama favors Israelis or Palestinians, what their opinions are of the American President’s proposals for the Middle East, and their overall opinion of Obama (in terms of trustworthiness, competence, honesty, warmth, intelligence, and fairness).

The results reveal that the group of Israeli Jews who saw the “Barack Hussein Obama” reference perceived him as less pro-Israeli; they considered his approaches to the peace process less fair or feasible; and felt that he is a less positive person overall - in comparison to the other half of this group who saw the “Barack Obama” reference.

For the Israeli Arabs “Barack Hussein Obama” also favored Israelis less, compared to those who saw “Barack Obama”. (Nevertheless, and in contrast to the study’s predictions, the study found that for Israeli Arabs “Barack Hussein Obama” is a less positive individual than “Barack Obama”.)

An interesting finding unrelated to the President’s middle name is that overall Israeli Jews perceived the American President as more pro-Palestinian and less pro-Israeli than the Israeli Arabs perceived him; but he also was perceived by this Jewish group as a more positive person and as one whose positions are more fair and feasible than the Israeli Arabs did.

According to the researchers, the President’s middle name makes Israelis - Jews and Arabs - perceive him as less pro-Israel, ultimately effecting an opinion amongst the Jews that he is less fair and amongst the Arabs that he is more fair.

It appeared that amongst the American participants of the study, their President’s middle name had no effect, and no major differences were noted between the groups that saw “Barack Hussein Obama” and “Barack Obama”. However, the study observed overall differences between the Israeli sympathizers and the Palestinian sympathizers in that the former perceived Obama as more pro-Palestinian and less pro-Israeli than the others.

In an attempt to understand the cultural impact of the name “Hussein”, the researchers took another sample group of Israeli Jews, Israeli Arabs, and Americans and asked them to rank associations with the names “Mike”, “Diego”, “Hussein”, and “Jean-Pierre”. The name “Hussein” was the only name that aroused negative associations among the Jewish Israelis and Americans, while the name aroused positive associations among the Arabs.

“In a world of global media, a seemingly irrelevant detail such as a middle name can affect particular audiences to develop an affinity or aversion to a person,” concludes Dr. Natalie Jomini Stroud. “It seems that a politician’s decision to use a middle name or omit it - as Obama did in his Cairo speech - can have an impact on certain members of the public.”

Friday, September 28, 2012

Alloy Key To Unlimited Cheap Energy From Water Says Study

Computer simulations of a metal–sulfide alloy unlock the secrets to designing solar-powered catalysts that generate hydrogen fuel from water.

Splitting water molecules  to produce hydrogen will become more efficient with newfound knowledge on the key electronic properties needed to turn special alloys into a long-lived photocatalyst.

 CC © Likablerodent

Partnerships can pay off when it comes to converting solar into chemical energy. By modeling a cadmium sulfide (CdS)–zinc sulfide (ZnS) alloy with special computational techniques, a Singapore-based research team has identified the key photocatalytic properties that enable this chemical duo to ‘split’ water molecules into a fuel, hydrogen gas (H2). The theoretical study was published by Jianwei Zheng from the A*STAR Institute of High Performance Computing and his co-workers.

Chemists had already identified CdS and ZnS semiconductors as promising photocatalysts for water splitting. However, both came with a drawback related to the size of their so-called ‘band gap’ — the energy difference between occupied and unoccupied electronic states that determine photo-activity. While CdS can readily harvest solar energy because of its small band gap, it needs a metal co-catalyst to produce H2. On the other hand, ZnS requires high-energy ultraviolet light to initiate water splitting owing to its large band gap.

Recently chemists had overcome these problems by alloying CdS and ZnS together into a ‘solid solution’: a physical state where Zn ions are distributed homogenously inside the crystal lattice of CdS. Altering the proportion of ZnS in these alloys enables production of photocatalysts with tunable responses to visible light and high H2 evolution rates in water. Improving the design of a Cd–ZnS solid solution is difficult, because its underlying mechanism is poorly understood.

As a workaround, Zheng and his co-workers used a technique known as ‘special quasi-random structures’ (SQS) to mimic a completely random alloy with a series of small, periodic models. After carefully working to correlate experimental random hexagonal crystals with their SQS approximations, they calculated the electronic properties of the Cd–ZnS solid solution using hybrid density functional theory — a computational method that gives accurate descriptions of band gaps.

When the researchers gradually increased the Zn content of their model alloy, they saw that the band gap deviated from a linear combination of the two components. This effect, known as band ‘bowing’, arises from volume deformations within the Cd–ZnS solid solution and is an essential parameter for predicting catalytic solar H2 production.

Further calculations revealed that the alloy’s high catalytic activity stemmed from obvious elevation of the position of unoccupied electronic states, and a subtle change in the position of occupied electronic states, as the amount of Zn increased. But to retain strong light harvesting capabilities and to avoid premature corrosion, the team proposes an equal ratio of ZnS to CdS for optimal photocatalytic water splitting.

The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing

References: Wu, J.-C., Zheng, J.-W., Zacherl, C. L., Wu, P., Liu, Z.-K. & Xu R. Hybrid functionals study of band bowing, band edges and electronic structures of Cd1–xZnxS solid solution. Journal of Physical Chemistry C 115, 19741–19748 (2011).

Associated links
A*STAR Research
A*STAR Institute of High Performance Computing
Link to original article in the Journal of Physical Chemistry C

Curiosity’s DAN Instrument Suggests Gale Crater Drier Than Expected

Preliminary data from the Curiosity Mars Science Laboratory, presented at the European Planetary Science Conference on 28 September, indicate that the Gale Crater landing site might be drier than expected.

Detecting water on Mars using the DAN instrument The DAN instrument works by firing a pulse of neutrons at the ground beneath the Curiosity rover. If they hit hydrogen (as a component of water ice) the neutrons’ kinetic energy is significantly reduced, while other materials in the ground affect the neutrons far less.

Credit: Russian Federal Space Agency/NASA.JPL-Caltech

The Curiosity rover is designed to carry out research into whether Mars was ever able to support life, and a key element of this search is the hunt for water. Although Mars has many features on its surface that suggest a distant past in which the planet had abundant liquid water in the form of rivers and lakes, the only water known to be abundant on Mars today is frozen, embedded in the soil, and in large ice caps at both poles. 

Gale Crater 
© NASA / JPL-Caltech / ESA / DLR / FU Berlin / MSSS
 © NASA / JPL-Caltech / ESA / DLR / FU Berlin / MSSS

The Dynamic Albedo of Neutrons (DAN) instrument on board Curiosity is designed to detect the location and abundance of water thanks to the way hydrogen (one of water’s components) reflects neutrons. When neutrons hit heavy particles, they bounce off with little loss in energy, but when they hit hydrogen atoms (which are much lighter and have approximately the same mass as neutrons), they lose half of their energy.

The DAN instrument works by firing a pulse of neutrons at the ground beneath the rover and detecting the way it is reflected. The intensity of the reflection depends on the proportion of water in the ground, while the time the pulse takes to reach the detector is a function of the depth at which the water is located. 

The location of the DAN Instrument on the Curiosity rover This image of NASA's Curiosity rover shows the location of the two components of the Dynamic Albedo of Neutrons instrument. The neutron generator is mounted on the right hip (visible in this view), and the detectors are on the opposite hip. 
Location of the two components of the Dynamic Albedo of Neutrons instrument
Image credit: NASA/JPL-Caltech

“The prediction based on previous measurements using the Mars Odyssey orbiter was that the soil in Gale Crater would be around 6% water. But the preliminary results from Curiosity show only a fraction of this,” said Maxim Mokrousov (Russian Space Research Institute), the lead designer of the instrument.

One possible explanation of the discrepancy lies in the variability of water content across the surface of Mars. There are large-scale variations, with polar regions in particular having high abundances of water, but also substantial local differences even within individual regions on Mars.

The Mars Odyssey spacecraft is only able to measure water abundance for an area around 300 by 300 kilometres – it cannot make high resolution maps. It may therefore be that Odyssey’s figure for Gale Crater is an accurate (but somewhat misleading) average of significantly varying hydrogen abundances in different parts the crater.

Indeed, over the small distance that the rover has already covered, DAN has observed variations in the detector counting rates that may indicate different levels of hydrogen in the ground, hinting that this is likely to be the case.

Curiosity’s ability to probe the water content in the martian soil in specific locations, rather than averages of broad regions, allows for a far more precise and detailed understanding of the distribution of water ice on Mars.


Contacts and sources:
Maxim Mokrousov
Russian Space Research Institute, Moscow
Europlanet R.I/

Titan Shows Surprising Seasonal Changes

Detailed observations of Saturn’s moon Titan have now spanned 30 years, covering an entire solar orbit for this distant world. Dr Athena Coustenis from the Paris-Meudon Observatory in France has analysed data gathered over this time and has found that the changing seasons of Titan affect it more than previously thought. Dr Coustenis presented these results at the European Planetary Science Congress in Madrid on Friday 28th September.

This real photograph of Titan shows two thin haze layers, now known to change with the seasons. 
Credit: NASA/JPL/Cassini.

Explains Dr Coustenis, “As with Earth, conditions on Titan change with its seasons. We can see differences in atmospheric temperatures, chemical composition and circulation patterns, especially at the poles. For example, hydrocarbon lakes form around the north polar region during winter due to colder temperatures and condensation. Also, a haze layer surrounding Titan at the northern pole is significantly reduced during the equinox because of the atmospheric circulation patterns. This is all very surprising because we didn’t expect to find any such rapid changes, especially in the deeper layers of the atmosphere.”

An artist’s impression of the Cassini spacecraft performing a fly-by of Titan, gathering data used in this research. 
Credit: NASA/JPL-Caltech.

The main cause of these cycles is solar radiation. This is the dominant energy source for Titan’s atmosphere, breaking up the nitrogen and methane present to create more complex molecules, such as ethane, and acting as the driving force for chemical changes. Titan is inclined at around 27 degrees, similar to the Earth, meaning that the cause of seasons – sunlight reaching different areas with varying intensity due to the tilt – is the same for both worlds. Says Dr Coustenis, “It’s amazing to think that the Sun still dominates over other energy sources even as far out as Titan, over 1.5 billion kilometres from us.”

This impression of Titan’s surface is based on data from the Huygens mission, giving an idea the view from the ground. 
Credit: Cassini-Huygens DISR.

To draw these conclusions data was analysed from several different missions, including Voyager 1 (1980), the Infrared Space Observatory (1997), and Cassini (2004 onwards), complemented by ground-based observations. Each season on Titan spans around 7.5 years, while it takes 29.5 years for Saturn to orbit the Sun, so data has now been gathered for an entire Titan year, encapsulating all seasons.

Different missions have gathered data on Titan over a full course of its seasons. 
Credit: Ralph Lorenz.

Dr Coustenis explains why it is important to investigate this distant moon: “Titan is the best opportunity we have to study conditions very similar to our own planet in terms of climate, meteorology and astrobiology and at the same time a unique world on its own, a paradise for exploring new geological, atmospheric and internal processes.”

The Europlanet Research Infrastructure is a major (€6 million) programme co-funded by the European Union under the Seventh Framework Programme of the European Commission. The Europlanet Research Infrastructure brings together the European planetary science community through a range of Networking Activities, aimed at fostering a culture of cooperation in the field of planetary sciences, 


Contacts and sources:
Dr Athena Coustenis
Europlanet R.I.

Time Bomb: Millions Of Pounds Of Unexploded Bombs In Gulf Poses Threat To Shipping, Says Texas A&M Proffesor

Millions of pounds of unexploded bombs and other military ordnance that were dumped decades ago in the Gulf of Mexico, as well as off the coasts of both the Atlantic and Pacific oceans, could now pose serious threats to shipping lanes and the 4,000 oil and gas rigs in the Gulf, warns two Texas A&M University oceanographers. 

A crab sits on a mustard gas canister that appears to be leaking.

Credit: Texas A&M University

William Bryant and Neil Slowey, professors of oceanography who have more than 90 years of combined research experience in all of the Earth's oceans, along with fellow researcher Mike Kemp of Washington, D.C., say millions of pounds of bombs are scattered over the Gulf of Mexico and also off the coasts of at least 16 states, from New Jersey to Hawaii.

Bryant says the discarded bombs are hardly a secret. "This has been well known for decades by many people in marine science and oceanography," he explains.

He will give a presentation in San Juan, Puerto Rico Monday (Oct. 1) about the bombs to a group of oceanographers and marine scientists in a conference titled "International Dialogue on Underwater Munitions."

"This subject has been very well documented through the years," Bryant explains. "My first thought when I saw the news reports of the Deepwater Horizon explosion in the Gulf two years ago were, 'Oh my gosh, I wonder if some of the bombs down there are to blame.'"

Military dumping of unused bombs into the Gulf and other sites started in 1946 and continued until 1970, when it was finally banned.

Millions of pounds – no one, including the military, knows how many – were sent to the ocean floor as numerous bases tried to lessen the amount of ordnance at their respective locations.

"The best guess is that at least 31 million pounds of bombs were dumped, but that could be a very conservative estimate," Bryant notes.

"And these were all kinds of bombs, from land mines to the standard military bombs, also several types of chemical weapons. Our military also dumped bombs offshore that they got from Nazi Germany right after World War II. No one seems to know where all of them are and what condition they are in today."

Photos show that some of the chemical weapons canisters, such as those that carried mustard gas, appear to be leaking materials and are damaged.

"Is there an environmental risk? We don't know, and that in itself is reason to worry," explains Bryant. "We just don't know much at all about these bombs, and it's been 40 to 60 years that they've been down there."

With the ship traffic needed to support the 4,000 energy rigs, not to mention commercial fishing, cruise lines and other activities, the Gulf can be a sort of marine interstate highway system of its own. There are an estimated 30,000 workers on the oil and gas rigs at any given moment.

The bombs are no stranger to Bryant and Slowey, who have come across them numerous times while conducting various research projects in the Gulf, and they have photographed many of them sitting on the Gulf floor like so many bowling pins, some in areas cleared for oil and gas platform installation.

"We surveyed some of them on trips to the Gulf within the past few years," he notes. "Ten are about 60 miles out and others are about 100 miles out. The next closest dump site to Texas is in Louisiana, not far from where the Mississippi River delta area is in the Gulf. Some shrimpers have recovered bombs and drums of mustard gas in their fishing nets."

Bombs used in the military in the 1940s through the 1970s ranged from 250- to 500- and even 1,000-pound explosives, some of them the size of file cabinets. The military has a term for such unused bombs: UXO, or unexploded ordnance.

"Record keeping of these dump sites seems to be sketchy and incomplete at best. Even the military people don't know where all of them are, and if they don't know, that means no one really knows," Bryant adds. He believes that some munitions were "short dumped," meaning they were discarded outside designated dumping areas.

The subject of the disposal of munitions at sea has been discussed at several offshore technology conferences in recent years, and it was a topic at an international conference several years ago in Poland, Bryant says.

"The bottom line is that these bombs are a threat today and no one knows how to deal with the situation," Bryant says. "If chemical agents are leaking from some of them, that's a real problem. If many of them are still capable of exploding, that's another big problem.

"There is a real need to research the locations of these bombs and to determine if any are leaking materials that could be harmful to marine life and humans," Bryant says.

For more information about the underwater munitions conference, go to http://www.underwatermunitions.org/

 
Contacts and sources:
Keith Randall
Texas A&M University

Throwing Asteroids From Their Orbits, Making Planets Into Giant Electromagnetic Generators, Pulsars Wreak Havoc

Pulsars are among the most extreme stars in the Universe: dense balls of matter which are heavier than the Sun, yet only a few tens of kilometres in diameter. They rotate rapidly (up to several hundred revolutions per second) and flash like lighthouse beacons – hence the name, which is short for pulsating star. And yet despite these exotic properties, pulsars are like our Sun in one way at least: two have been observed to be home to planetary systems. 

Planets around a pulsar: This artist's impression shows the planetary system around pulsar PSR B1257+12, one of two pulsars known to be host to at least one planet. Research by Fabrice Mottez (Paris Observatory), presented at the European Planetary Sciences Congress on 28 September, finds that planets around pulsars may have powerful electromagnetic wakes around them. These wakes have implications both for how pulsar planets form, and for how they can be detected.

Credit: NASA/JPL-Caltech/R. Hurt (SSC)

In work presented to the European Planetary Science Congress in Madrid on Friday 28 September, Fabrice Mottez (Paris Observatory) makes a series of predictions about the properties of planetary systems around pulsars. His team’s work has implications both for how to discover these planets, and for their formation, evolution and properties.

"Pulsars and their planetary systems work a bit like giant electric generators," says Mottez. "If the conditions are right, the magnetic field and stellar wind of the pulsar can interact with planets and create a powerful electromagnetic wake around the planets."

This phenomenon may be visible from Earth, which would provide a new method of detecting planets around pulsars. But it has even greater importance for how pulsar planet systems evolve.

When objects such as stars or planets radiate, they lose energy. And while the forces unleashed by the wakes around pulsar planets are not large enough to have a major effect on the planets’ orbits, they are expected to have much more profound effects on smaller bodies like asteroids and comets.

"Depending on the direction of their orbits, asteroids and comets could be thrown out into distant orbits or dragged down onto the pulsar's surface. Even for objects as big as a kilometre in diameter, this could happen in less than 10 000 years, which is very rapid on astronomical timescales," says Mottez. 

The Crab pulsar: This image, which combines data from the Hubble Space Telescope (visible light), Spitzer Space Telescope (infrared) and Chandra X-ray Observatory (X-rays) shows the Crab Pulsar. The X-ray emissions (in blue) show the location of high-energy phenomena around the rapidly spinning star. The visible and infrared light (shown in red) traces the location of debris thrown out by the supernova that destroyed the Crab Pulsar’s progenitor star. Although it is not known whether the Crab Pulsar has planets, it is thought that the debris surrounding pulsars can form planetary systems. Work by Fabrice Mottez (Paris Observatory), presented at the European Planetary Sciences Congress on 28 September, shows how electromagnetic phenomena in pulsar systems can greatly affect the motion of small bodies like asteroids and comets that form the building blocks of planets. 
Credit: X-Ray: NASA/CXC/J.Hester (ASU); Optical: NASA/ESA/J.Hester & A.Loll (ASU); Infrared: NASA/JPL-Caltech/R.Gehrz (Univ. Minn.)

While these phenomena have only a small impact on the orbital motions of planets, Mottez's work is an important step towards better understanding how circumpulsar planets may form.

Pulsars are the dense cores leftover from large stars after they explode in a supernova. Although supernovae are extremely violent, it is thought that planets surrounding an exploding star can survive the blast, albeit in a heavily disrupted orbit. However, planetary survivors like these are not the only kind of planet that could in theory exist around a pulsar.

Planets form from discs of matter that gradually accrete around stars, usually when the star has just been born. However, it is thought that the debris thrown out by supernovae could provide material that triggers a second burst of planet formation around pulsars, shortly after the explosion.

The disruptive effects of the electromagnetic wake on small objects could have profound consequences for the formation of such second generation planets.
 
Contacts and sources:
Fabrice Mottez  

NASA Sees Sun Unleash A Wide, But Benign, CME

NASA's Solar and Heliospheric Observatory captured this image of a particularly wide coronal mass ejection (CME) that erupted from the sun at 10:23 p.m. EDT on Sep. 27, 2012. The leading edge of the CME appears to wrap around over half of the entire sun as it moves out into space. 
SOHO captured this earth-directed halo CME on Sept. 27, 2012.
Credit: SOHO/ESA & NASA

The sun erupted with a wide, Earth-directed coronal mass ejection (CME) on Sept. 27, 2012 at 10:25 p.m. EDT. CMEs are a phenomenon that can send billions of tons of solar particles into space that can reach Earth one to three days later, affecting electronic systems in satellites and on the ground. Experimental NASA research models estimate that the CME is traveling at around 700 miles per second and will reach Earth on Sept. 29.

CMEs of these speeds are usually benign. In the past, similar CMEs have caused auroras near the poles but have not caused disruption to electrical systems or significantly interfered with GPS or satellite-based communications systems.

The CME is associated with a fairly small solar flare that was measured as C-class, which is third in strength after X- and M-class flares. The flare peaked at 7 p.m. EDT and came from an active region on the sun labeled AR 1577.

NOAA's Space Weather Prediction Center (http://swpc.noaa.gov) is the United States Government official source for space weather forecasts.

What is a CME?

For answers to this and other space weather questions, please visit the Spaceweather Frequently Asked Questions page.


Contacts and sources:
Karen C. Fox
NASA Goddard Space Flight Center, Greenbelt, MD

Flesh-Eating Disease And "Genetic Engineers"

Royal Society University Research Fellow Dr Edward Taylor, from the University of Lincoln’s School of Life Sciences, is carrying out research on bacteriophage that play a role in flesh-eating disease.

Dr Taylor spent the last ten years at the University of York where he was awarded a Royal Society University Research Fellowship in 2006. He has chosen to continue his research at the University of Lincoln, with funding continuing for a further two years.

Phage protein crystals
Credit: University of Lincoln

Bacteriophage (often called phage) are viruses that infect bacteria. These are extremely common and mostly harmless; however some play a role in diseases such as diphtheria, cholera, dysentery, botulism, necrotizing (flesh-eating) pneumonia, toxic shock and scarlet fever.

Phages are nature’s “genetic engineers”, frequently swapping genes between bacterial strains. This happens by the phage attaching itself to the surface of the cell, making a hole and then injecting its own DNA into the bacteria. Occasionally this DNA becomes integrated into the bacterial chromosome where it lays dormant, but more commonly the phage is active straight away. The bacterial metabolism is hijacked, the DNA de-coded and new phages are produced in great numbers. Finally the bacterium is burst open and the new virus particles escape.

This inactive/active life style allows the phage to cleverly separate its outbreaks over long periods of time. Some phage which infect harmful bacteria carry toxin and other genes which when decoded interact with our immune systems, tying them together, giving the phage and bacteria a better chance of survival. Some phages also destroy bacteria.

Dr Taylor works on a particular phage which infects a flesh-eating bacterium called ‘Streptococcus pyogens’. This carries a toxin and DNase genes, which when expressed go on to damage the immune system causing scarlet fever, “toxic shock” and more invasive necrotizing forms of infection.

Dr Taylor said: “This research will allow for a fundamental understanding of bacterial pathogenicity and the role of viruses in disease processes. The overall aim is to carry out an in-depth structural study on one phage that prompts Streptococci to become toxigenic. I am studying complexes of the viral proteins using a technique – known as X-ray crystallography. This enables me to “see” the individual atoms within a protein. I am particularly interested in the mechanism of enzymes which break down DNA. These have been shown to help the Streptococcus pyogenes evade capture by the immune system and promote more invasive necrotizing forms of infection. I am studying these enzymes by making small changes to the protein structure and seeing what effect this has on the way the enzyme works. Through these changes I hope to gain a better understanding of the disease process.”

It was through focused research with Professor Gideon Davis during his time at the University of York that led Dr Taylor to develop his own interests in the interplay between certain pathogenic bacteria and their compatible bacteriophage.

Contacts and sources:
University of Lincoln