Before you say no, consider this; when you think of peanut butter, you probably also think of jelly, and then probably bread.
Or, when you remember the fun you had skiing last winter, you may then also think of the hot chocolate you had afterward, what clothes you were wearing on the slopes, the actual trip to the ski resort and so on.
As one memory connects with another, you eventually develop a scenario in your mind which takes you an event from your past.
Call it mental time-traveling.
But being able to explain this phenomenon, called linked memories or episodic memory, has proved difficult to pin down.
According to Kahana, the newly published study provides the first neurobiological evidence that memories formed in the same context become linked.
The participants, all epilepsy patients, had between 50 and 150 electrodes implanted throughout their brains, allowing Kahana’s team to directly record brain activity.
While studying these brain recordings, researchers noticed that when patients recalled a word, they’d bring back – not only the thoughts associated with the word itself – but also remnants of thoughts associated with other words they studied nearby in time.
The scientists say their findings provide a brain-based explanation of a memory phenomenon that people experience every day.
Kahana points out potential benefits of the study’s findings.
If scientists understand the biological machinery behind recording and retrieving the memories of a person’s life events, they might be able to design devices – perhaps in the form of implantable chips – to help memory-impaired patients or those with anxiety disorders such as post traumatic stress disorder (PTSD).
This weekend on the “Science World” radio program, Professor Kahana tells us about the research and findings of his team’s study.
Listen to it here…
[audio://blogs.voanews.com/science-world/files/2011/07/Science-World-One-On-One-Dr.-Michael-Kahana-Linked-Memories.mp3|titles=Science World One-On-One – Dr. Michael Kahana – Linked Memories]
Other stories we cover on the “Science World” radio program this week include:
Science Scanner: Windpipe Made from Stem Cells Transplanted into Ailing Man
Trachea made from patient’s stem cells being prepared for transplant (Image: David Green, Harvard Bioscience)
In what seems like the plot of a science fiction novel, researchers successfully built and transplanted a new windpipe for an Eritrean man who had a rare but deadly form of tracheal cancer.
Although human tissue has been generated outside the body, the trachea transplant is a first, according to David Green of Harvard Bioscience, which designed and built the bio-reactor used to seed the patient’s stem cells onto a synthetic scaffold holding device.
According to Green, the construction of the scaffold and bio-reactor was done under extreme time pressure, because the patient had a very short period of time in which the operation might be successful.”
The process – as described by Green – seems nothing short of miraculous.
Just a few days before surgery, bone marrow was taken from the patient’s hip bone. From that, about 40 milliliters of stem cell material were bathed over the surface of the very porous scaffold.
Research is under way already for generating more complex organs like hearts, kidneys and lungs. While such solid organ transplants may be years away, Green says the next stage is to expand the technology to other hollow organs like ureters, blood vessels and coronary arteries for bypass surgery. (From: Rebecca Ward/VOA)
Watch VOA reporter Rebecca Ward’s video story:
Scientists Devise an Invisibility Cloak
The cloak of invisibility is a staple in fairy tales and science fiction stories. In the popular Harry Potter series, the boy wizard is able to sneak into the forbidden areas of his school by wearing a magical cloak.
Now word comes that a group of scientists has, for the first time, devised an invisibility cloak material which hides objects from detection by using light that people can see.
According to a new report in the American Chemical Society journal “Nano Letters,” this new device marks a leap forward in cloaking materials. Most of the cloaks used in previous experiments were made from materials that only work with microwave or infrared waves, which can’t be seen by the human eye.
Professor Zhang’s group wanted to go beyond this and develop methods that use light frequencies which can be seen. The researchers devised a reflective “carpet cloak” out of layers of silicon oxide and silicon nitride etched into special patterns.
The researchers’ carpet cloak works by concealing an object under its layers, and bends the light waves away from the bump that the object makes, so that the surface of the cloak looks flat and smooth like a normal mirror.
The object that was cloaked in this study was microscopic in size, roughly the diameter of a red blood cell. But, the researchers say that despite this experimental size, their cloaking device has demonstrated that it may be capable of cloaking any object underneath a reflective carpet layer.
And, that unlike other previous demonstrations that were limited to infrared or other invisible light, their work makes actual invisibility for the light that can be seen by the human eye.
Organized Crime Linked to Disappearance of Endangered Species
Organized crime plays a significant role in the worldwide decline of animal species such as rhinos, tigers and elephants, according to a new paper by Elizabeth Bennett, a respected conservationist at the Wildlife Conservation Society.
Bennett asserts that an immense, increasingly sophisticated illegal trade in wildlife parts is being conducted by organized crime. This, along with what the group considers to be old and outdated law enforcement methods, leads to the decimation of some of the world’s most beloved species.
The study reports that these syndicates develop and employ sophisticated smuggling operations which penetrate even the most secure wildlife populations.
Much of this illicit trade is reportedly driven by wealthy East Asian markets, which have an insatiable appetite for wildlife parts.
Tricks and methods the crime syndicates employ include hidden compartments in shipping containers, rapidly changing their smuggling routes and using Internet technology – such as e-commerce – to make their locations difficult to detect.
“We have taken our eye off the ball,” Bennett says. “Enforcement is critical – old fashioned in concept but needing increasingly advanced methods – to challenge the ever-more sophisticated methods of smuggling.”
Bennett is concerned some of the most beloved, charismatic species of wildlife will continue to disappear – possibly to the point of extinction – unless wildlife crimes are taken seriously and resources allocated and committed to tackling the sophisticated, well-funded, globally-linked criminal operations.
Is Your Smart-Phone Habit Forming?
It seems that everyone has and loves their so-called smart phone; so much so that there’s concern over the repetitive and obsessive use of these high-tech devices.
Using data collected in both Finland and the U.S., researchers in Helsinki collected scientific evidence of what they call “checking habits” – repetitive checks of the phone’s menu screen, news, email, contacts and various social applications.
According to their research, a typical “checking” lasts less than 30 seconds and involves opening the screen lock and accessing a single application.
The data indicates that the users engaged in their checking habits as long as they were awake.
Interestingly, the research also goes on to say that these “checkings” don’t happen randomly and for no reason; they are associated with a small set of contexts that trigger them. These include reading email when commuting or checking news while bored.
Although these checking habits have become quite common, the actual smart phone users didn’t consider their checking behavior to be an addiction, but look at it simply as overuse and an annoyance.
The authors conclude that this uniquely 21st Century behavior has its pros and cons. On one hand, by making interesting information available so quickly, content developers have made the device more useful.
But, on the other hand, the habits that emerge from this increasingly popular media devour more and more of a person’s free time.
The study is the first to discover a correlation between optimism and stroke.
According to the U.S. National Institutes of Health, a stroke – also called a brain attack – happens when blood flow to a part of the brain is interrupted due to a blood vessel in the brain being blocked or bursting open.
If blood flow is stopped for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing permanent damage.
Researchers studied 6,044 people over 50 years old and had them rate their optimism levels on a 16-point scale.
In order to establish the link between optimism and stroke, the team employed a special analysis technique which was adjusted for various factors that might affect stroke risk.
These factors included chronic illness, smoking, alcohol use, race, gender, marital status, blood pressure, body mass index and level of physical activity, as well as psychological conditions.
Over a two-year follow-up period, and after adjusting for age of the study participants, they found that each point increase in optimism corresponded to a 9 percent decrease in acute stroke risk.
In reviewing the research data, study authors found that people who looked at life optimistically tended to pay more attention to their health and took the necessary steps to promote better health such as taking vitamins, eating a healthy diet and exercising.
The study team also found some evidence suggesting positive thinking alone might have a biological impact as well.
Similar past studies show that people with sunnier dispositions experience health benefits such as having a healthier immune system, experiencing faster wound healing and having a lower risk of heart disease.
Got HIV? Plan on a Long Life
HIV-infected people in Africa should plan on being around for a long time, according to a new study, which shows patients who take a combination of HIV medications can expect to live a near-normal lifespan.
The study suggests that those who undergo cART – even in resource-limited settings – should no longer automatically assume an HIV diagnosis is a death sentence.
Released this week, the findings provide much needed hope for those who suffer from HIV.
Dr. Edward Mills, the study’s principal investigator, says HIV-infected people “should plan and prepare for a long and fulfilling life.”
The study also points out that since female study participants had a significantly longer life expectancy than the men, women should start treatment as early as possible.
Scientists involved with the study say this encouraging report provides the first large-scale analysis of life expectancy outcomes in Africa for HIV patients on cART.
Although the study was conducted in Uganda, researchers say the situation there is similar to many other African countries, where simplified HIV/AIDS care in rural to urban areas is available.
Life expectancy at birth in Uganda is approximately 55 years and increases as people survive key life events.
According to the study, life expectancy for 20-year-old HIV patients on the combination antiretroviral therapy was an additional 26.7 years, and those who are 35 can live an additional 27.9 years.
The report’s authors say their study should be seen as further evidence that global investment in various HIV and AIDS programs is working.
This weekend on the “Science World” radio program, Dr. Mills talks more about the team’s research and shares his thoughts on the findings.
Listen to an excerpt of our interview here:
[audio://blogs.voanews.com/science-world/files/2011/07/One-On-One-Dr.-Edward-Mills-HIV_Patients-Could-Have-Normal-Lifespans-Radio-Edit.mp3|titles=One On One – Dr. Edward Mills – HIV_Patients Could Have Normal Lifespans – Radio Edit]
Or you can listen to the full version here:
[audio://blogs.voanews.com/science-world/files/2011/07/One-On-One-Dr.-Edward-Mills-HIV_Patients-Could-Have-Normal-Lifespans-Full-Version.mp3|titles=One On One – Dr. Edward Mills – HIV_Patients Could Have Normal Lifespans – Full Version]
Other stories we cover on the “Science World” radio program this week include:
Science Scanner: Jumping on the Asteroid Belt Between Mars and Jupiter
In the first stop of its mission to explore the origins of the solar system, NASA’s space probe Dawn sent back its first close-up picture of the giant asteroid Vesta on Friday, July 15.
Dawn is the very first spacecraft to orbit around an object in the main asteroid belt between Mars and Jupiter.
Vesta is 530 kilometers in diameter and is the second most massive object in the asteroid belt. Scientists at NASA’s Jet Propulsion Laboratory say that the image shows Vesta in greater detail than ever before.
Dawn’s ambitious mission began with its launch from Cape Canaveral, Florida on Sept. 27, 2007.
After spending a year orbiting Vesta, Dawn heads to the largest and most massive object in the asteroid belt, the dwarf planet Ceres, where it’s expected to arrive in February 2015.
Dawn will provide data to help scientists understand the earliest chapter of our solar system, which also paves the way for future human space missions.
The Dawn space probe is propelled by ion engines, which expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available.
The most advanced such device ever, it’s expected to be thousands of times more powerful than the Hubble telescope.
Spektr-R, the first deep-space observatory launched by Moscow in 25 years, has been plagued by delays since the 1980s.
While Russia is taking the lead, Spektr-R involves scientists from 20 nations, who are either providing on-board hardware or offering co-operation from their terrestrial antennas.
According to Roskosmos, the Russian space agency, Spektr-R will scour the fringes of the universe for black holes, mysterious quasar radio sources and the fast-rotating stellar remnants known as pulsars.
Rock, Paper, Scissors Illustrates a Natural Human Behavior
Most of us, at one time or another, have played the two-person hand game, “Rock, paper, scissors“.
A recently published study shows that players of the game tend to subconsciously copy each other’s hand shapes, which significantly increases the chance of the game ending in a draw.
The researchers gathered 45 people to play rock-paper-scissors in one of two conditions.
In one of the conditions, both of the players were blindfolded. In the other, only one player was blindfolded and the other was not.
When both participants were blindfolded, one-third of the games ended in a draw, exactly as chance predicts.
But when only one player was blindfolded, significantly more games ended in a draw.
The researchers say that this suggests that the sighted player was most likely copying the gestures of the blindfolded one – even when it was best for them not to do so.
Richard Cook at the University College of London was a lead author of the study. “This experience causes the impulse to imitate to become so ingrained it is often subconscious,” he says. “For example, when one person starts tapping their foot in a waiting room it is not uncommon for the whole room to start tapping their feet without thinking.”
The study also confirmed that imitation is often ‘automatic’ in the sense of being hard to stop.
Did Humans Walk Millions of Years Earlier than We Thought?
Ancient footprints suggest that one of our human ancestors began walking nearly four million years ago, almost two million years earlier than previously thought.
According to researchers, the prints show features of the foot which bear more similarities to the gait of modern humans, than to the bipedal walking used by primates such as chimpanzees, orangutans and gorillas.
The footprints were found at a site in Laetoli, Tanzania, which contains the earliest known trail made by human ancestors. There are 11 individual prints in good condition.
Past studies of the footprints have been primarily based on the examination of single prints. Researchers might have misinterpreted artificial features and conditions such as erosion and other environmental factors as reflecting the actual features of the footprint.
The scientists said that the foot function represented by the prints is most similar to patterns seen in modern humans. This is important because the development of human foot function helped our ancestors expand further out of Africa.
The research team hopes to determine when our ancestors first walked, or ran, over very long distances, a function which helped humans travel and populate the world.
The second phase of a project to acquire a 3-D view of the magnetic fields on and around the moon launches this weekend.
On Sunday, July 17, the second of two space probes will join its twin as it drops into a permanent orbit around the moon.
While the two probes will have similar orbits, each will move in an opposite direction.
The two spacecraft, built by the University of California, Berkeley, comprise what NASA calls its ARTEMUS mission.
ARTEMUS stands for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun.
As soon as the second ARTEMUS space probe assumes its orbit, both will immediately begin the first-ever twin satellite observations of the lunar surface, its magnetic field and the surrounding magnetic environment.
Both ARTEMUS spacecraft were originally launched into Earth’s orbit with three other probes in February 2007, as part of NASA’s THEMIS (Time History of Events and Macroscale Interactions during Substorms)mission.
THEMIS explored how the sun’s magnetic field and the million-mile-per-hour solar wind interacted with Earth’s magnetic field on the side of our planet opposite the sun.
After completing their roles with the THEMIS mission, the ARTIMIS pair was put into a long meandering orbit which set them on a path to the moon.
“These are the most fully equipped spacecraft that have ever gone to the moon,” says David Sibeck, THEMIS and ARTEMIS project scientist at the Goddard Space Flight Center (GSFC) in Maryland. “For the first time we’re getting a unique, two-point perspective of the moon from two spacecraft, and that will be a major component of our overall lunar research program.”
The ARTEMIS probes will join NASA’s Lunar Reconnaissance Orbiter, which has been in orbit around the moon since 2009, taking high-resolution photographs and looking for signs of water ice.
This September, NASA is scheduled to launch two GRAIL (Gravity Recovery and Interior Laboratory) spacecraft to map the moon’s gravitational field.
And, in 2013, the agency plans to launch LADEE (Lunar Atmosphere and Dust Environment Explorer) to characterize the lunar atmosphere and dust environment.
Vassilis Angelopoulos, principal investigator for the THEMIS and ARTEMIS missions and a professor of space physics at UCLA, says the exploration is cost-effective, too.
“ARTEMIS will be doing totally new science, as well as reusing existing spacecraft to save a lot of taxpayer money.”
Science Scanner: Catching a Comet’s Kamikaze Move
For the first time ever, NASA has captured images of a comet flying into the sun.
The occurrence is not that unusual. It even has a name; sungrazer. What makes this sighting unique is that, up to this point, no one has actually seen the end of a comet’s journey.
NASA’s Solar Dynamics Observatory (SDO) spacecraft recorded a 20-minute movie of the comet flying directly in front of the sun on July 5.
Scientists are excited, not only because it’s a first, but also because they’re looking forward to analyzing the data to learn more about the fate of the comet.
Since the sun cranks out such incredible heat and radiation, it’s likely the comet simply evaporated completely away.
Scientists in the U.S. and Australia have found evidence that drug addiction may be related to our powerful primal appetite for salt.
A study conducted by Duke University in Durham, NC and Melbourne University in Melbourne, Australia finds that addictive drugs affect the same nerve cells and connections in the brain that tap an ancient instinctual desire for salt, a much-needed element in our diets.
The minerals found in salt help maintain a number of body functions and are necessary not only for staying healthy, but also for simply staying alive.
The scientists found that the gene patterns activated by stimulating an instinctive behavior such as our hunger for salt were the same as those regulated by cocaine or opiate addiction.
The study’s co-lead author Wolfgang Liedtke, an assistant professor of Medicine and Neurobiology at Duke University, says the group’s findings have profound and far-reaching medical implications – from providing a basis of understanding drug addictions to the detrimental consequences when obesity-generating foods are overloaded with sodium.
The study was published in the Proceedings of the National Academy of Sciences early edition online on July 11.
Chain of Underwater Volcanoes Discovered Near Antarctica
British scientists have found 12 previously unknown volcanoes under the ocean waters around the South Sandwich Islands, which are located about half-way between South America and Antarctica.
They also found craters with a diameter of five-kilometers, left by collapsing volcanoes. Seven active volcanoes are visible above the sea as a chain of islands.
The research reveals that the sub-sea landscape surrounding the underwater volcanoes, with waters warmed by volcanic activity, has become a rich habitat for many species of wildlife, which could lead to valuable new insights about life on Earth.
The researchers say their findings will help us understand what happens when volcanoes erupt or collapse underwater, as well as their potential for creating dangerous phenomena such as tsunamis.
This may sound like the plot to the 1980’s movie “War Games,” in which a young computer whiz hacks into a military computer which learns to launch weapons of mass destruction by playing games.
What if a computer could not only read, but also actually understand the meaning of a sentence written in virtually any language?
They’re trying to get a computer to analyze and follow a set of instructions for an unfamiliar task and, so far, they say they’ve had success with it.
As part of their experimentation in developing this technology, the research team is teaching a computer to play “Civilization,” a complex computer game in which the player guides the development of a city into an empire across centuries of human history.
When the researchers programmed the computer system to use a player’s manual to help it develop game-playing strategy, its rate of victory jumped from 46 percent to 79 percent.
“Games are used as a test bed for artificial-intelligence techniques simply because of their complexity,” says S. R. K. Branavan, a graduate student at MIT and a member of this research team. “Every action that you take in the game doesn’t have a predetermined outcome, because the game or the opponent can randomly react to what you do. So you need a technique that can handle very complex scenarios that react in potentially random ways.”
The researchers hope to demonstrate that computer systems that learn the meanings of words through exploratory interaction with their environments are a promising subject for further research.
Work is also under way to use the algorithms they’ve already developed with robotic systems, too.
When flying through the clouds, the planes force the air nearby to expand and cool rapidly. This causes the water droplets within the cloud to freeze – first into ice and then snow – as the precipitation falls toward the ground.
Afterward, the clouds are often left with odd-shaped gaps, which make it look as if someone used a giant hole-punch on the cloud.
The researchers think this phenomenon, which some consider inadvertent cloud seeding, occurs at a number of other airports as well, especially those located in mid- to high-latitude areas during colder months.
One element that seems to be a key variable is whether there are cloud layers in the vicinity which contain water droplets at temperatures far below freezing, which is quite common.
The study team says more research is needed to determine whether the precipitation produced by this effect is significant.
Do certain species survive at the expense of others? The question of competition between the species was at the heart of a premise first explored by Charles Darwin in 1859. A new study lends further support to this aspect of Darwin’s still-controversial theory of natural selection.
Darwin’s “On the Origin of Species by Means of Natural Selection” outlined a revolutionary approach which would eventually become known as evolutionary biology. Today, more than a century later, scientists continue to try to either prove or disprove Darwin’s theories.
One of Darwin’s hypotheses explored the role competition played in determining the survival of a species. A recently released study led by Lin Jiang at Georgia Institute of Biology – otherwise known as Georgia Tech – supports this theory.
Although most scientists already tend to accept Darwin’s premise, this new study presents the strongest direct experimental evidence yet to support its validity.
Dr. Jiang’s team chose to study 10 common species of the ciliated protist – or protozoa microrganisms – because of their ability to reproduce. This allowed the research team to examine the co-existence of the species over multiple generations in just a few weeks.
The research team conducted their experiments within specially constructed, artificial and simplified ecosystems called microcosms.
When left alone in a microcosm, all of the species survived until the end of the experiment. However, when two species were paired together, one dominated in more than half of the experiments, leading to the extinction of the other species.
The team found that extinction occurred faster and more often between the species of microorganisms that were more closely related. Dr. Jiang says this aspect of the study supports Darwin’s theory, referred to as the phylogenetic limiting similarity hypothesis.
This hypothesis is just one of the many Darwin published in “The Origin of Species.” It was through this book that Darwin introduced the scientific theory that populations evolve over the course of generations through a process of natural selection.
This weekend on the “Science World” radio program, Dr. Jiang explains this hypothesis and talks to us about his team’s research and what else they learned from their studies.
Listen to the interview here…
[audio://blogs.voanews.com/science-world/files/2011/07/One-On-One-Dr.-Lin-Jiang-Web.mp3|titles=One On One – Dr. Lin Jiang – Web]
Other stories we cover on the “Science World” radio program this week include:
Final mission of the Space Shuttle program is under way
Oil spill on Montana’s Yellowstone River spikes concern over pipeline safety
Early CT scans boost survival rates for smokers with lung cancer
Science Scanner: Why Food is Like a Drug
“You can’t eat just one.”
That was a slogan used by a large potato chip company years ago. Turns out, it might have been scientifically correct.
Researchers in a new study say fatty but delightful snacks like chips trigger natural, marijuana-like chemicals in our bodies which make them nearly irresistible.
For a long time, craving carbohydrates was blamed for our overindulging in these goodies.
But, University of California, Irvine scientists have discovered that the foods contain fats which trigger a natural biological mechanism that drives people to over snack.
Yes, I heard cannabis (the scientific term for marijuana) in that name, too. These endocannabinoids are natural marijuana-like chemicals produced by our own bodies.
The team discovered that when rats tasted something fatty, cells in their upper gut region started producing these endocannabinoids.
Interestingly, sugars and proteins did not have this effect.
The team’s research could play an important role in the international battle against obesity. The research suggests that, by developing medications designed to obstruct endocannabinoid activity, the cravings and overindulgence of fatty foods can be reduced.
It’s happened to most of us at one time or another – we’re outside enjoying a warm sunny day and forget to put on the sunblock. A while later, it dawns on us that perhaps we’ve been enjoying the sun a little too much. Our skin is a bit red, tender and warm to the touch.
But that’s only the beginning, because medical experts say that, although the initial symptoms of a sunburn appear within a few hours, the full effect to your skin may not appear for 24 hours or longer.
Now, scientists in London say they’ve discovered why sunburns are painful.
Researchers at King’s College believe they’ve traced the cause to a molecule in the body which controls sensitivity to pain from UVB irradiation.
The molecule is called CXCL5 and is part of a group of proteins called chemokines. These proteins act as lures which attract inflammatory immune cells to the injured tissue, which in turn triggers pain and tenderness.
The research team says its study is the first to reveal the role CXCL5 plays in facilitating pain. The discovery could lead to new medicines to treat pain caused by other common inflammatory conditions, such as arthritis.
Preparations continue at the Kennedy Space Center for the scheduled July 8 launch of Atlantis, the final flight of the space shuttle program.
One of the experiments the crew will conduct during this final shuttle mission involves testing a new therapy NASA hopes will build bone mass during space travel.
Astronauts lose a significant amount of bone mass during space travel. There’s concern that this bone loss could lead to an increased chance of fractures for those who take on long-duration flights.
The research findings will not only impact space travelers, but might also offer new insight into the prevention and treatment of osteoporosis, bone fractures and skeletal fragility among those who are inactive due to aging or illness.
An international team of astronomers says it has found hydrogen peroxide (H2O2) in space.
The formation of this compound is important to both astronomers and chemists, since it is closely linked to oxygen and water, which are critical for life.
And, since much of the water here on Earth is thought to have originated in space, scientists are anxious to learn and understand just how it is created.
This area of space happens to contain very cold (around -250 degrees Celsius), dense clouds of cosmic gas and dust in which new stars are being born.
Scientists describe these clouds as being comprised mostly of hydrogen, but they also contain traces of other chemicals.
Since the APEX telescope can observe light at very small wavelengths, the research team was able to find the characteristic signature of light emitted by hydrogen peroxide, coming from part of the Rho Ophiuchi clouds.
The researchers say that this new detection of hydrogen peroxide will help astronomers better understand the formation of water in the universe.
