(Photo: Nicolas Holzheu via Flickr/Creative Commons)
People can tell how old you are by how you smell, according to new research published in the journal PLoS One.
It appears that “old person smell” some people complain about is for real, that elderly people emit a unique identifying odor.
An elderly individual’s “old person smell” is actually acknowledged and accepted in cultures throughout the world. In Japan, there’s a special word, kareishū, that describes it.
Funny thing though, according to the research, all age groups rated “old person smell” as less intense and less unpleasant than the body odors of middle-aged and young individuals.
Our sense of smell, coupled with our unique body odor, provides us with a very powerful and effective method of non-verbal communication.
The body odors of other, non-human animals, hold a wide assortment of a number of chemical components that can communicate a wide variety of social information. Scientists say that the intensities of the chemical behind those odors and how they are perceived by others tend to change throughout a person’s life.
“Similar to other animals, humans can extract signals from body odors that allow us to identify biological age, avoid sick individuals, pick a suitable partner and distinguish kin from non-kin,” said Johan Lundström, senior report author, who is a sensory neuroscientist at the Monell Chemical Senses Center in Philadelphia, Penn.
Scientists have theories regarding how these age-related odors relate to mating and how they help animals choose their suitable mates. For example, certain scents might suggest that older males are more desirable because they contribute genes that allow offspring to live longer, while older females might be avoided because their reproductive systems are more fragile.
In conducting the research for the study, scientists collected samples of body odor from people in three age groups. Those between 20 and 30 years old were considered to be the young group, those 45 to 55 were the middle-age group and the old age group was made up with people between 75 and 95 years-old, with 12 to 16 people per group.
Each test subject slept in an unscented t-shirt that contained underarm pads for five nights. These pads where then cut into four pieces and placed into separate glass jars.
A group of 41 young (20 to 30 years old) people served as evaluators and were each given two of the test jars in nine combinations and were asked to identify which of the samples came from older people and evaluate the odors based on intensity and how pleasant each one was. These young evaluators were then asked to give an estimate as to the age of the donor of each sample.
The evaluators were able to differentiate people in each of the three donor age groups based strictly on odor. Odors from the old-age group drove the evaluator’s ability to discern age. The researcher also said that they found that the young evaluators rated the old-age body odors as being less intense and not as unpleasant as the odors from the young and middle-age groups.
“Elderly people have a discernible underarm odor that younger people consider to be fairly neutral and not very unpleasant,” said Lundström. “This was surprising given the popular conception of old age odor as disagreeable. However, it is possible that other sources of body odors, such as skin or breath, may have different qualities.”
In future studies, the researchers will try to identify the primary biomarkers that evaluators use to identify age-related odors and to determine how the brain is able to identify and measure this information.
Took 10 Million Years for Life on Earth to ‘Re-set’ After Mass Extinction
A catastrophic event such as increased volcanism may have contributed to massive extinction event (Photo: National Park Service)
More than 250 million years ago, most life on Earth was wiped out by a catastrophic event called the Permian–Triassic extinction. New research suggests it took our planet 10 million years to recover from what is now known as “The Great Dying.”
The Great Dying took place millions of years earlier than the Cretaceous-Tertiary extinction, which killed off the dinosaurs 65 million years ago. It was also much more devastating, destroying 90 percent of all plants and animals.
For some time now, they’ve debated how quickly life on Earth bounced back from this mass extinction. A new article in Nature Geoscience puts that number at 10 million years.
Artist rendering of The Great Dying in which 90 percent of all marine species are thought to have perished. (Image: Lunar and Planetary Institute)
So why did it take our planet so long to recover from this devastating loss of life? Why didn’t life just “bounce back?”
The sheer intensity of this crisis, coupled with the bleak conditions which remained on Earth after that first devastating surge of extinction, are the reasons for the delay, according to the report authors.
These bleak conditions continued, in bursts, for some five-to-six million years after the initial calamity, triggering repeated environmental crises.
“Life seemed to be getting back to normal when another crisis hit and set it back again,” said Michael Benton, one of the report authors who is a professor at England’s University of Bristol. “The carbon crises were repeated many times and then, finally, conditions became normal again after five million years or so.”
Map of the world around the time of the Great Dying (Image: Dr. Ron Blakey via Wikimedia Commons)
While certain groups of marine and land animals recovered quickly to a certain point, they suffered continual setbacks with each of these bursts of dire conditions following the initial crisis because, according to the researchers, their permanent ecosystems were not firmly established.
But after the waves of environmental devastation began to wane, not only did life return to Earth, but much more complex ecosystems were formed, allowing for much more sophisticated life forms which eventually led to human life.
“We often see mass extinctions as entirely negative but in this most devastating case, life did recover, after many millions of years, and new groups emerged,” Benton said. “The event had re-set evolution. However, the causes of the killing – global warming, acid rain, ocean acidification – sound eerily familiar to us today. Perhaps we can learn something from these ancient events.”
NASA Checks Out Potentially Hazardous Asteroids
NASA finds there are more potentially hazardous asteroids (PHA)s, closely aligned with the plane of our solar system than previous models suggested. (Image: NASA/JPL-Caltech)
First, the good news. There are fewer asteroids near Earth than previously estimated. Now the bad news. A new NASA survey also finds there may be more than twice as many aligned with Earth’s orbit than thought, which could increase the odds of an asteroid coming close enough to us to cause concern.
Potentially hazardous asteroids, or PHA’s, are a subset of a larger group of near-Earth asteroids, which come within eight million kilometers of us and are big enough to pass through Earth’s atmosphere, causing a great amount of damage.
To get a count on how many of these possible troublemakers are out there, NASA used one of its space telescopes to make an assessment of our solar system’s population of PHA’s.
WISE, an unmanned satellite carrying an infrared heat-sensitive telescope, was launched in December 2009 and spent a little over a year imaging the entire sky to provide data on asteroids, the coolest and dimmest stars, and the most radiant galaxies.
Approximately 4,700 PHAs, give or take about 1,500, with diameters larger than 100 meters, were found, according to NEOWISE principal investigator Amy Mainzer.
Most of the asteroids in our solar system never get close to Earth. They’re found in what’s called the Asteroid Belt, which is between the orbits of Mars and Jupiter.
But, occasionally, if there is an interaction with one of the giant planets, some of the asteroids may be forced to wander away from the main belt and into near-Earth space – causing concern for those of here on terra firma.
To make their tally, Mainzer along with her colleagues at JPL examined approximately 107 PHA’s with WISE telescope data, providing them with a representative sample of the total population of these potentially dangerous objects.
From that sample, Mainzer’s team was able to calculate the total number of PHA’s in the solar system.
This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid (PHA) (orange). (Image: NASA/JPL-Caltech)
Of course, the big question remains how likely is it that one of these potentially-hazardous asteroids actually could strike Earth. Mainzer, looking back at Earth’s history, points out that major asteroid strikes very rarely happen. Scientists estimate that such a major hit happens every 100 million years or so. The last mammoth asteroid collided with Earth about 65 million years ago, causing, scientists think, the extinction of most life on our planet, including the dinosaurs.
Mainzer says astronomers have already discovered most of the significant asteroids out there. However, she warns, there are many smaller asteroids, which haven’t been discovered yet. The NEOWISE study indicates that only between 20 and 30 percent of these have been discovered so far.
To keep us safer from asteroid impacts, Mainzer says the most important thing that we can do is actually go look for them. “Because, if you don’t know where they are, you have no idea how to really deal with any risk,” she says.
Mainzer and her colleagues are currently working on a proposal to build and carry out an advanced survey mission. Called the Near Earth Object Camera (NEOCam), this proposed mission would locate many more asteroids to provide a more accurate picture of the total asteroid population.
Dr. Amy Mainzer joins us on this week’s radio edition of Science World. Check out the right column for scheduled air-times or listen to the interview with Dr. Mainzer below.
Other stories we cover on the “Science World” radio program this week include:
SpaceX Marks New Commercial Era in Space Exploration
Yesterday’s successful launch of SpaceX‘s Falcon 9 rocket and Dragon reusable spacecraft from Cape Canaveral in Florida, marked what NASA administrator Charles Bolden called “the beginning of a new era in exploration.”
Artist rendering of the Dragon Spacecraft with Solar Panels deployed (Image: SpaceX)
Before that happens, Dragon will perform a flyby of the space station this Thursday. From a distance of approximately 2.41 kilometers from the ISS, technicians will validate the operation of the spacecraft’s sensors and flight systems necessary for a safe rendezvous.
If everything checks out, the Dragon capsule will be cleared to rendezvous and berth with the ISS on Friday, May 25. The ISS crew will use the space station’s robotic arm to capture Dragon and install it on the bottom side of the Harmony node of the ISS.
Modern private spaceflight began in 1980 with the European Space Agency’s creation of Arianespace, which produces, operates and markets the Ariane series of launch vehicles. Since 1984, Arianespace has conducted more than 240 commercial space launches.
Private involvement of spaceflight can also be traced back to the 1962 U.S. Communications Satellite Act, legislation which provided a pathway for corporations to own and operate their own satellites. However, those satellites were still sent into space by government-owned launch vehicles.
Since retiring its space shuttle program last year, NASA – the US space agency – has partnered with companies to deliver crew and cargo to the ISS.
Artist rendering of Orbital's Cygnus spacecraft approaching the International Space Station. (Image: Orbital)
Along with the SpaceX Dragon reusable spacecraft, Orbital Sciences is developing a vehicle that will also deliver supplies and other material to the ISS. Its Cygnus spacecraft is an expendable space capsule and is expected to launch its demonstration mission to the ISS sometime later this year.
A program called Commercial Crew Development (CCDev) has been established and is being run by NASA to attract companies that would develop privately-operated crew vehicles to ferry crew members to and from the ISS and other destinations in low-Earth orbit.
Thousands of years of cross-breeding have made it difficult for scientists to trace the ancient genetic roots of today’s dogs.
Still, British researchers gave it a try. They recently compared genetic data from 1,375 modern-day dogs, from 35 different breeds, to global archeological records of dog remains.
Although, other genetic studies suggest dogs descended from the grey wolf, the researchers found modern dog breeds, genetically speaking, have little in common with their ancient ancestors.
Dogs were the first animals domesticated by man about 15,000 years ago. However, we really didn’t start keeping them as pets until about 2,000 years ago. Even so, until fairly recently, most dogs were kept and used to perform specific jobs.
Although some dog breeds – such as the Akita, Afghan Hound and the Chinese Shar-Pei – have been classified as ancient by canine experts, they’re no closer to the first domesticated dogs than any other modern breeds. This, according to the study, is again due to cross-breeding through the years.
Breeds like the Saluki appear genetically different because they were geographically isolated and were not part of the 19th century efforts to blend lineages to create most of the breeds we keep as pets today. (Photo: Keith Dobney)
Lead author Greger Larson, an evolutionary biologist in Durham University’s Department of Archaeology, said, “Ironically, the ubiquity of dogs combined with their deep history has obscured their origins and made it difficult for us to know how dogs became man’s best friend. All dogs have undergone significant amounts of cross-breeding to the point that we have not yet been able to trace all the way back to their very first ancestors.”
But the researchers say their new study shows the unique genetic signatures in these dogs were not necessarily due to being directly descended from ancient dogs, but merely appeared to be genetically different because they were geographically isolated and were not part of the 19th Century kennel clubs which blended various lineages in order to create most of the breeds we’re familiar with today.
As DNA sequencing becomes faster and cheaper, the scientists are hopeful more research will provide further insight into the evolution and domestication of our canine friends.
Manmade Retina Could Restore Vision to Millions
The Photovoltaic Retinal Prothesis system (Graphic: Palanker Lab at Stanford University)
For those afflicted with AMD, it can be difficult or even impossible to read or recognize faces. However, in most cases, sufferers retain enough peripheral vision to allow for other activities of daily life.
AMD ranks third worldwide as a cause of blindness, behind cataract and glaucoma, and is the primary cause of sight loss in industrialized countries, according to the World Health Organization (WHO).
“The prosthetic retina we are developing has been partly inspired by cochlear implants for the ear but with a camera instead of a microphone and, where many cochlear implants have a few channels, we are designing the retina to deal with millions of light-sensitive nerve cells and sensory outputs,” said Keith Mathieson, one of the team’s lead researchers.
The researchers at Stanford University in California hope to make their Photovoltaic Retinal Prosthesis device much simpler in design and operation than existing similar units.
A scene as it might be viewed by a person with age-related macular degeneration. (Image: National Eye Institute, National Institutes of Health)
While AMD attacks the eye’s photoreceptors, which are its image-capturing cells, the prosthetic retina works by electrically stimulating neurons in the retina that have been left relatively untouched by the ravages of the disease.
This new device uses “video goggles” to transport energy and images directly to the eye. The unit operates remotely by pulsed near infrared light that stimulates the retina and produces visual perception in the patient.
Since the device requires no wires, surgical implantation will be simpler than many current prosthetic retinas, which are driven by coils and often require complex surgery to be implanted.
“The current implants are very bulky, and the surgery to place the intraocular wiring for receiving, processing and power is difficult,” said Stanford’s Daniel Palanker, who led the research. “With our device, the surgeon needs only to create a small pocket beneath the retina and then slip the photovoltaic cells inside it.”
Initial tests of the Photovoltaic Retinal Prothesis have been encouraging, according to an article published in Nature Photonics, and the device is now being further developed.
Exercise Offsets Muscle Breakdown in Heart Patients
Exercise can curb muscle breakdown in heart failure patients (Photo: National Institutes of Health)
We all know physical activity is good for us, and now new research suggests regular exercise can also help the aging and those suffering from heart failure.
In fact, researchers say, maintaining a regular physical workout can offset the breakdown of muscle, increase strength, reduce inflammation and condition the body to handle even more exercise.
And, the good news is, it doesn’t matter how old the patient is.
Heart failure, a potentially deadly condition, occurs when the heart can’t keep up with its workload. If the heart muscle cannot pump enough blood, it cannot meet the body’s needs for blood and oxygen.
As a result, those with heart-failure get tired easily and can have shortness of breath. Activities most of us take for granted, such as walking, climbing stairs or other actions that require even mild exertion, can become very difficult for those with this condition.
For their study, researchers recruited 60 heart-failure patients and 60 healthy volunteers in 2005 and 2008. Half of each of these two groups consisted of people 55 years and younger, while the other half was 65 years and older, allowing for an average age difference of 20 years between the groups.
Even a casual walk can fatigue someone with heart failure (Photo: Michael Cohen via Flickr/Creative Commons)
Half of the people in each age group were assigned, at random, to four weeks of supervised aerobic training, while the other half was told not to exercise during that time.
Before each group began their assigned schedule of exercises, or non-exercise, the researchers took biopsies from the thigh muscles of all the study subjects. The muscle samples were taken again after the four-week test period.
Those assigned to the exercise group had four 20-minute periods of aerobic exercise every day for five days a week and also participated in one weekly 60-minute group exercise session.
The leg muscle strength of those in the exercise group was measured before they began their exercise program and once it concluded four weeks later.
The researchers found that all who exercised had increased their muscle force endurance and oxygen uptake – a measure of how much oxygen a body is consuming at any given time. The heart failure patients 55 and under had increased their peak oxygen uptake by 25 percent, while those 65 and over increased it by 27 percent. Both the younger and older groups of heart failure patients showed increased muscle strength after the four-week exercise program, but their muscle size was unaffected.
“Exercise switches off the muscle-wasting pathways and switches on pathways involved in muscle growth, counteracting muscle loss and exercise intolerance in heart failure patients,” Gielen said.
The study authors believe their research could lead to possible treatment of the muscle breakdown and wasting associated with heart failure.
Dr. Gielen joins us with more insight on this week’s radio edition of “Science World.” See right column for scheduled times, or check out the interview with Dr. Gielen below.
Other stories we cover on the “Science World” radio program this week include:
A woman uses the BrainGate system to mentally control a robotic arm and reach for a drink. (Photo: The BrainGate Collaboration)
Almost 15 years after being paralyzed by a stroke, a 58-year-old woman was able to reach for, pick up and take a sip of a drink, by using her thoughts to operate a robotic arm. Up until then, the woman had depended upon caregivers to do this for her.
As technology continues to meld man with machine, BrainGate – a multidisciplinary team of researchers – has spent years developing these human/robotic-type systems.
While the team’s innovations show significant promise for people with brain injuries and disorders, the technology is years away from practical use.
A new report, published in Nature, examines clinical trials of the device, which focus on the system’s durability and its potential for long-term use.
Part of the BrainGate system is implanted in the brain to capture the neural signals that control intentional movement.
“Years after the onset of paralysis, we found that it was still possible to record brain signals that carry multi-dimensional information about movement and that those signals could be used to move an external device,” said Dr. Leigh Hochberg, the clinical trials lead investigator.
The group’s neural interface system has a baby aspirin-sized sensor that monitors brain signals. The sensor is implanted into the motor cortex, the part of the brain that controls movement. The brain signals picked up by the sensor are then fed into a computer system outfitted with specially-designed software and hardware which turn the brain signals into digital commands, which in turn drive external devices such as robotics systems.
The latest trial research studied two stroke patients, the 58-year-old woman and a 66-year-old man. Both study subjects were unable to speak or move their limbs because of brainstem strokes they suffered years ago. During the experiment, both were taught to perform complex tasks with a robotic arm by imagining the movements of their own arms and hands.
Dr. John Donoghue, who leads the development of BrainGate technology, is especially encouraged by the woman’s ability to use the BrainGate neural interface system because her stroke happened nearly 15 years ago and her sensor was implanted more than five years ago.
The research team was concerned neurons in the motor cortex might die or stop generating meaningful signals after years of disuse and that, after years since implantation, the sensor might break down and become less effective at enabling complex motor functions
The BrainGate research team’s ideal system would be wireless, fully automated and able to provide decades of stable operation. However, to achieve that goal, they must continue trial studies and test the technology in more individuals.
UItimately, BrainGate hopes to develop a system which reconnects the brains of those suffering from paralysis directly to their paralyzed limbs, rather than with robotic ones.
Website Puts Earth’s Animal Species at Your Fingertips
Screen-shot Map of Life (Image: Yale University)
A new website, built on a Google Maps platform, allows anyone with an Internet connection to map the known global distribution of nearly all of Earth’s species, including mammals, birds, amphibians and reptiles, as well as the fresh water fish of North America.
This initial version of “Map of Life” shows how all of Earth’s animals are geographically distributed throughout the world.
“It is the where and the when of a species,” says Walter Jetz, associate professor of ecology and evolutionary biology at Yale University, who helped lead the project. “It puts at your fingertips the geographic diversity of life. Ultimately, the hope is for this literally to include hundreds of thousands of animals and plants, and show how much or indeed how little we know of their whereabouts.”
The team anticipates “Map of Life” will be a useful tool for a number of people, including professional scientists, wildlife and land managers, ecological and conservation organizations, as well as interested members of the general public.
(Map of Life demo)
Data for the project includes contributions from various museums; local and regional checklists; and observations recorded by both professional and amateur scientists.
The map is expected to grow as additional data is continuously added by both professionals and amateurs, allowing researchers to identify and fill knowledge gaps, while at the same time offering a unique tool which can be used to detect change over a period of time.
Just how in-depth and extensive the map will be depends upon the continual input, support and participation by others in the scientific community. In future versions, the mapping tool will offer various mechanisms for users to supply new or missing information.
Fundamentally, the map is, “an infrastructure, something to help us all collaborate, improve, share, and understand the still extremely limited geographic knowledge about biodiversity,” Jetz says.
Why Children Choose the Snacks They Do
Little girl snacks on cotton candy (Photo: AP Photo/Carolyn Kaster)
Attitudes, relationships, intentions and personal behavior control are all factors which influence whether children reach for junk food rather than opting for healthy snacks, such as fruit and vegetables.
A University of Cincinnati study finds intentions are a major factor behind a child’s snack choices. This is driven by several variables, such as the child’s attitude toward eating healthy or unhealthy foods, as well as the social or peer pressure the child feels.
While we all love to snack from time to time, we don’t always go for the healthier choice, opting instead for junk food, which is high in calories but low in nutritional value.
Children are no different when it comes to snacking, but as awareness of childhood obesity continues to rise, researchers and public health officials are increasing their scrutiny of children’s eating habits, including what they choose to eat as snacks. Zeroing in on the problem of obesity in children is an important public health concern and could help prevent future health threats such as diabetes and heart disease.
The study points to the strong influence of parents, teachers and other adults kids know and trust. If a parent or teacher has good snacking or eating habits, this can influence what the child eats well, too.
The amount of control children feel they have over snacking is another factor influencing snack choice; in other words, if they are given the freedom to choose their own snacks rather than having them already selected for them.
The study did find that snacking was a major part of the children’s caloric intake, about 300 calories a day from foods like chips, candy and cookies. These so-called high-calorie, low-nutrition foods made up around 17 percent of the kids’ daily caloric needs. Only 45 calories of the study group’s daily intake came from healthy snacks like fruits and vegetables.
Healthy choice - boy eating an apple (Photo: AP Photo/Jacqueline Arzt)
Researchers also examined whether children thought selecting lower-calorie snacks over the high-calorie versions was a good idea; how confident there were in knowing how to pick the lower-calorie snack foods; and whether they were influenced or felt pressure from their parents, teachers or friends in picking the lower-calorie snacks.
The demographics of the children in the study group were varied and included a mix of boys and girls, Caucasians, African-Americans, Hispanics and Asian-Americans.
There are also differences in snack choices along the lines of gender and ethnicity. Girls in the study tended to eat more of the high-calorie snacks, taking in an average of 348.3 calories a day, while boys consumed around 238.8 calories each day.
African-American children ate the smallest amount of high-calorie snacks, at 221.6 calories a day. Hispanic children consumed 297.6 snack calories daily, followed by Caucasian children who ate 282.3 calories a day. Asian-American children who took in about 280.8 calories a day.
Among the ethnic groups measured, the study also finds that both Hispanic and Asian-American children consume more of the healthier snacks, such as fruit and vegetables, than both Caucasian and African-American children.
The study’s authors say their research suggests more care and concern should be given to what foods children choose for their snacks, because they’re relatively cheap and easy for children to buy.
You can listen to what Dr. Paul Branscum, one of the study’s authors, says about the study, what it revealed and how important it is to the future health of our children to pay attention to their choices of snack foods and encourage healthier eating habits.