Eating Fish, Nuts May Not Help Thinking Skills After All

Contrary to earlier studies, new research suggests that omega-3 fatty acids may not benefit thinking skills. The study is published in the September 25, 2013, online issue of Neurology®, the medical journal of the American Academy of Neurology. Omega-3s are found in fatty fish such as salmon and in nuts.

"There has been a lot of interest in omega-3s as a way to prevent or delay cognitive decline, but unfortunately our study did not find a protective effect in older women. In addition, most randomized trials of omega-3 supplements have not found an effect," said study author Eric Ammann, MS, of the University of Iowa in Iowa City. "However, we do not recommend that people change their diet based on these results. Researchers continue to study the relationship between omega-3s and the health of the heart, blood vessels, and brain. We know that fish and nuts can be healthy alternatives to red meat and full-fat dairy products, which are high in saturated fats."

The study involved 2,157 women age 65 to 80 who were enrolled in the Women's Health Initiative clinical trials of hormone therapy. The women were given annual tests of thinking and memory skills for an average of six years. Blood tests were taken to measure the amount of omega-3s in the participants' blood before the start of the study.

The researchers found no difference between the women with high and low levels of omega-3s in the blood at the time of the first memory tests. There was also no difference between the two groups in how fast their thinking skills declined over time

Source : Science Daily

N.H.Khider

Emissions of CO2 driving rapid oceans 'acid trip'

The world's oceans are becoming acidic at an "unprecedented rate" and may be souring more rapidly than at any time in the past 300 million years.

In their strongest statement yet on this issue, scientists say acidification could increase by 170% by 2100.

They say that some 30% of ocean species are unlikely to survive in these conditions.

The researchers conclude that human emissions of CO2 are clearly to blame.

The study will be presented at global climate talks in Poland next week.

In 2012, over 500 of the world's leading experts on ocean acidification gathered in California. Led by the International Biosphere-Geosphere Programme, a review of the state of the science has now been published.

This Summary for Policymakers states with "very high confidence" that increasing acidification is caused by human activities which are adding 24 million tonnes of CO2 to oceans every day.

Pickled waters

The addition of so much carbon has altered the chemistry of the waters.

Since the start of the industrial revolution, the waters have become 26% more acidic.

"This is the state of the art," said Prof Jean-Pierre Gattuso, from CNRS, the French national research agency.

"My colleagues have not found in the geological record, rates of change that are faster than the ones we see today."

What worries the scientists is the potential impact on many ocean species including corals

.Studies carried out at deep sea vents where the waters are naturally acidic thanks to CO2, indicate that around 30% of the ocean's biodiversity may be lost by the end of this century.

These vents may be a "window on the future" according to the researchers.

Continue reading the main story       

"You don't find a mollusc at the pH level expected for 2100, this is really quite a stunning fact," said Prof Gattuso.

"It's an imperfect window, only the ocean's acidity is increasing at these sites, they don't reflect the warming we will see this century.

"If you combine the two, it could be even more dramatic than what we see at CO2 vents."

The effect of acidity is currently being felt most profoundly felt in the Arctic and Antarctic oceans. These chilly waters hold more CO2 and increasing levels of the gas are turning them acidic more rapidly than the rest of the world.

The more acidic they become, the more damaging they are to the shells and skeletons of marine organisms.

The researchers say that by 2020, ten percent of the Arctic will be inhospitable to species that build their shells from calcium carbonate. By 2100 the entire Arctic will be a hostile environment.

Sea snail Pteropods like this are already feeling the corrosive impact of acidic waters in the Antarctic

These effects are already visible says Prof Gattuso.

"In the Southern Ocean, we already see corrosion of pteropods which are like sea snails, in the ocean we see corrosion of the shell.

"They are a key component in the food chain, they are eaten by fish, birds and whales, so if one element is going then there is a cascading impact on the whole food chain."

The authors warn that the economic impact of the losses from aquaculture could be huge - the global cost of the decline in molluscs could be $130bn by 2100 if emissions of CO2 continue on their current pathway.

Adding alkaline substances such as crushed limestone to the waters has been mooted as a potential way of mitigating the worst impacts of acidification. But Prof Gattuso says it would only have a limited effect.

"Maybe in bays which have a restricted exchange with open oceans it may work, it may give some local relief.

"But the latest research is showing that it is not really practical at a global scale. It is very expensive and very energy intensive."

Marine protection zones would also give some short term benefit, but the scientists say that in the long term only significant cuts in emissions will slow the progress of acidification. 

By Matt McGrath Environment correspondent, BBC News.

H.SH

First Virtual Surgery with Google Glass

A University of Alabama at Birmingham surgical team has performed the first surgery using a virtual augmented reality technology called VIPAAR in conjunction with Google Glass, a wearable computer with an optical head-mounted display. The combination of the two technologies could be an important step toward the development of useful, practical telemedicine.

VIPAAR, which stands for Virtual Interactive Presence in Augmented Reality, is a UAB-developed technology that provides real time, two-way, interactive video conferencing.

UAB orthopedic surgeon Brent Ponce, M.D., performed a shoulder replacement surgery on Sept. 12, 2013 at UAB Highlands Hospital in Birmingham. Watching and interacting with Ponce via VIPAAR was Phani Dantuluri, M.D., from his office in Atlanta.

Ponce wore Google Glass during the operation. The built-in camera transmitted the image of the surgical field to Dantuluri. VIPAAR allowed Dantuluri, who saw on his computer monitor exactly what Ponce saw in the operating room, to introduce his hands into the virtual surgical field. Ponce saw Danturuli's hands as a ghostly image in his heads-up display.

"It's not unlike the line marking a first down that a television broadcast adds to the screen while televising a football game," said Ponce. "You see the line, although it's not really on the field. Using VIPAAR, a remote surgeon is able to put his or her hands into the surgical field and provide collaboration and assistance."

The two surgeons were able to discuss the case in a truly interactive fashion since Dantuluri could watch Ponce perform the surgery yet could introduce his hands into Ponce's view as if they were standing next to each other.

"It's real time, real life, right there, as opposed to a Skype or video conference call which allows for dialogue back and forth, but is not really interactive," said Ponce.

Ponce says VIPAAR allows the remote physician to point out anatomy, provide guidance or even demonstrate the proper positioning of instruments. He says it could be an invaluable tool for teaching residents, or helping surgeons first learning a new procedure.

"This system is able to provide that help from an expert who is not on site, guiding and teaching new skills while enhancing patient safety and outcomes," he said. "It provides a safety net to improve patient care by having that assistance from an expert who is not in the room."

"VIPAAR brings experts or collaborators to the site of need, in any field where a visual collaboration would be beneficial," said Drew Deaton, CEO of VIPAAR. "VIPAAR uses video on mobile devices to allow experts or collaborators to connect in real time and not only see what might need to be fixed, corrected or solved, but also be able to reach in, using tools or just their hands, and demonstrate. It's like being there, side by side with someone when you might be a thousand miles, or 10 thousand miles away."

"Today, you can't imagine having a phone without the capability to take picture, or a video," he said. "I can't imagine, five years from now, not being able to use a smart phone to connect to an expert to solve my problem. And have that person reach in and show me how to solve that problem, because the technology is advancing rapidly and we're bringing this technology to market today."

Source: science daily

B.N

Ants, Like Humans, Can Change Their Priorities

All animals have to make decisions every day. Where will they live and what will they eat? How will they protect themselves? They often have to make these decisions as a group, too, turning what may seem like a simple choice into a far more nuanced process. So, how do animals know what's best for their survival?

For the first time, Arizona State University researchers have discovered that at least in ants, animals can change their decision-making strategies based on experience. They can also use that experience to weigh different options.

The findings are featured today in the early online edition of the scientific journal Biology Letters, as well as in its Dec. 23 edition.

Co-authors Taka Sasaki and Stephen Pratt, both with ASU's School of Life Sciences, have studied insect collectives, such as ants, for years. Sasaki, a postdoctoral research associate, specializes in adapting psychological theories and experiments that are designed for humans to ants, hoping to understand how the collective decision-making process arises out of individually ignorant ants.

"The interesting thing is we can make decisions and ants can make decisions -- but ants do it collectively," said Sasaki. "So how different are we from ant colonies؟"

To answer this question, Sasaki and Pratt gave a number of Temnothorax rugatulus ant colonies a series of choices between two nests with differing qualities. In one treatment, the entrances of the nests had varied sizes, and in the other, the exposure to light was manipulated. Since these ants prefer both a smaller entrance size and a lower level of light exposure, they had to prioritize.

"It's kind of like a humans and buying a house," said Pratt, an associate professor with the school. "There's so many options to consider -- the size, the number of rooms, the neighborhood, the price, if there's a pool. The list goes on and on. And for the ants it's similar, since they live in cavities that can be dark or light, big or small. With all of these things, just like with a human house, it's very unlikely to find a home that has everything you want."

Pratt continued to explain that because it is impossible to find the perfect habitat, ants make various tradeoffs for certain qualities, ordering them in a queue of most important aspects. But, when faced with a decision between two different homes, the ants displayed a previously unseen level of intelligence.

According to their data, the series of choices the ants faced caused them to re-prioritize their preferences based on the type of decision they faced. Ants that had to choose a nest based on light level prioritized light level over entrance size in the final choice. On the other hand, ants that had to choose a nest based on entrance size ranked light level lower in the later experiment. 

This means that, like people, ants take the past into account when weighing options while making a choice. The difference is that ants somehow manage to do this as a colony without any dissent. While this research builds on groundwork previously laid down by Sasaki and Pratt, the newest experiments have already raised more questions.

"You have hundreds of these ants, and somehow they have to reach a consensus," Pratt said. "How do they do it without anyone in charge to tell them what to do?"

Pratt likened individual ants to individual neurons in the human brain. Both play a key role in the decision-making process, but no one understands how every neuron influences a decision.

Sasaki and Pratt hope to delve deeper into the realm of ant behavior so that one day, they can understand how individual ants influence the colony. Their greater goal is to apply what they discover to help society better understand how humanity can make collective decisions with the same ease ants display.

"This helps us learn how collective decision-making works and how it's different from individual decision-making," said Pratt. "And ants aren't the only animals that make collective decisions -- humans do, too. So maybe we can gain some general insight."

Source : Science Daily

H.SH

One in Five Sun-Like Stars May Have Earth-Size

Based on a statistical analysis of all the Kepler observations, University of California, Berkeley, and University of Hawaii, Manoa, astronomers now estimate that one in five stars like the sun have planets about the size of Earth and a surface temperature conducive to life.

Given that about 20 percent of stars are sun-like, the researchers say, that amounts to several tens of billions of potentially habitable, Earth-size planets in the Milky Way Galaxy.

"When you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye. That is amazing," said UC Berkeley graduate student Erik Petigura, who led the analysis of the Kepler data.

"It's been nearly 20 years since the discovery of the first extrasolar planet around a normal star. Since then, we have learned that most stars have planets of some size orbiting them, and that Earth-size planets are relatively common in close-in orbits that are too hot for life," said Andrew Howard, a former UC Berkeley post-doctoral fellow who is now on the faculty of the Institute for Astronomy at the University of Hawaii. "With this result, we've come home, in a sense, by showing that planets like our Earth are relatively common throughout the Milky Way Galaxy."

Petigura, Howard and Geoffrey Marcy, UC Berkeley professor of astronomy, will publish their analysis and findings this week in the online early edition of the journal Proceedings of the National Academy of Sciences.

Earth-size may not mean habitable

"For NASA, this discovery is really important, because future missions will try to take an actual picture of a planet, and the size of the telescope they have to build depends on how close the nearest Earth-size planets are," Howard said. "An abundance of planets orbiting nearby stars simplifies such follow-up missions."

The team cautioned that Earth-size planets in orbits about the size of Earth's are not necessarily hospitable to life, even if they reside in the habitable zone around a star where the temperature is not too hot and not too cold.

"Some may have thick atmospheres, making it so hot at the surface that DNA-like molecules would not survive. Others may have rocky surfaces that could harbor liquid water suitable for living organisms," Marcy said. "We don't know what range of planet types and their environments are suitable for life."

Last week, however, Howard, Marcy and their colleagues provided hope that many such planets actually are rocky and could support liquid water. They reported that one Earth-size planet discovered by Kepler -- albeit, a planet with a likely temperature of 2,000 Kelvin, which is far too hot for life as we know it -- is the same density as Earth and most likely composed of rock and iron, like Earth.

"This gives us some confidence that when we look out into the habitable zone, the planets Erik is describing may be Earth-size, rocky planets," Howard said.

Transiting planets

NASA launched the Kepler space telescope in 2009 to look for planets outside the solar system that cross in front of, or transit, their stars, which causes a slight diminution -- about one hundredth of 1 percent -- in the star's brightness. From among the 150,000 stars photographed every 30 minutes for four years, NASA's Kepler team reported more than 3,000 planet candidates. Many of these are much larger than Earth -- ranging from large planets with thick atmospheres, like Neptune, to gas giants like Jupiter -- or in orbits so close to their stars that they are roasted.

To sort them out, Petigura and his colleagues are using the Keck telescopes in Hawaii to obtain spectra of as many stars as possible. This will help them determine each star's true brightness and calculate the diameter of each transiting planet, with an emphasis on Earth-diameter planets.

Independently, Petigura, Howard and Marcy focused on the 42,000 stars that are like the sun or slightly cooler and smaller, and found 603 candidate planets orbiting them. Only 10 of these were Earth-size, that is, one to two times the diameter of Earth and orbiting their star at a distance where they are heated to lukewarm temperatures suitable for life. The team's definition of habitable is that a planet receives between four times and one-quarter the amount of light that Earth receives from the sun.

A census of extrasolar planets

What distinguishes the team's analysis from previous analyses of Kepler data is that they subjected Petigura's planet-finding algorithms to a battery of tests in order to measure how many habitable zone, Earth-size planets they missed. Petigura actually introduced fake planets into the Kepler data in order to determine which ones his software could detect and which it couldn't.

"What we're doing is taking a census of extrasolar planets, but we can't knock on every door. Only after injecting these fake planets and measuring how many we actually found could we really pin down the number of real planets that we missed," Petigura said.

Accounting for missed planets, as well as the fact that only a small fraction of planets are oriented so that they cross in front of their host star as seen from Earth, allowed them to estimate that 22 percent of all sun-like stars in the galaxy have Earth-size planets in their habitable zones.

"The primary goal of the Kepler mission was to answer the question, 'When you look up in the night sky, what fraction of the stars that you see have Earth-size planets at lukewarm temperatures so that water would not be frozen into ice or vaporized into steam, but remain a liquid, because liquid water is now understood to be the prerequisite for life?'" Marcy said. "Until now, no one knew exactly how common potentially habitable planets were around sun-like stars in the galaxy." 

All of the potentially habitable planets found in the team's survey are around K stars, which are cooler and slightly smaller than the sun, Petigura said. But the researchers' analysis shows that the result for K stars can be extrapolated to G stars like the sun. Had Kepler survived for an extended mission, it would have obtained enough data to directly detect a handful of Earth-size planets in the habitable zones of G-type stars.

"If the stars in the Kepler field are representative of stars in the solar neighborhood, … then the nearest (Earth-size) planet is expected to orbit a star that is less than 12 light-years from Earth and can be seen by the unaided eye," the researchers wrote in their paper. "Future instrumentation to image and take spectra of these Earths need only observe a few dozen nearby stars to detect a sample of Earth-size planets residing in the habitable zones of their host stars."

In January, the team reported a similar analysis of Kepler data for scorched planets that orbit close to their stars. The new, more complete analysis shows that "nature makes about as many planets in hospitable orbits as in close-in orbits," Howard said.

The research was funded by UC Berkeley and the National Science Foundation, with the assistance of the W. M. Keck Observatory and NASA.

Source:Science Daily

R.Sawas

Subcategories