Space Science and Exploration

Milky Way's Baby Stars Linked to Stellar Growth Spurt

This photo taken by astronomers using the South African Astronomical Observatory shows the center of our Milky Way galaxy and two beacon-like pulsating stars, known as Cepheids, that serve as distance signposts for astronomers. This image was released Aug. 24, 2011. CREDIT: N. Matsunaga View full size image

Star formation in the center of the Milky Way underwent a growth spurt approximately 25 million years ago.

After a slow period, the mass of baby stars that were created more than tripled, according to new research. Such a peak could indicate an influx of gas into the galactic bulge.

To figure out star birth rates, an accurate count of the ages of stars in the area first had to be determined.

 

An international team of astronomers turned the Infrared Survey Facility at the South African Astronomical Observatory toward the center of the galaxy in search of a special kind of pulsing star known as Cepheid variables. [Top 10 Star Mysteries]

"It is difficult to determine the ages of stars unless they have some special characteristic," primary author Noriyuki Matsunaga, of the University of Tokyo, told SPACE.com via email.

Counting stars

The steady strobe of Cepheids is related to their age. As they grow older, they flash faster and faster, allowing astronomers to determine just how long they've been around.

It takes stars approximately 10 million years to develop the pulse Cepheids are known for. The stars can last up to 200 million years before dying. This should have provided astronomers with a range of stars to study.

But oddly enough, the only Cepheids the astronomers located were all between 20 million and 30 million years old.

Matsunaga explained that the probability of seeing younger Cepheids was low. Because a star takes around 10 million years to evolve into a variable, it was possible that none of the stars within the field of view would have spent only 10 million years — a brief span of time, astronomically — as a Cepheid.

"On the other hand, the probability to see the older Cepheids is higher," Matsunaga said. "If stars 30 [million] to 70 million years old existed, we should have detected several." [Biggest Revelations of the Space Age]

Instead, they saw none.

"The absence of the shorter-period Cepheids was unexpected," Matsunaga said.

Stellar birth rates

Calculating star formation rates is an exercise in probability. Astronomers know how likely a Cepheid is to form, versus other, nonpulsing stars. The team took the three Cepheids they found and worked backward to determine star formation rates during the two periods.

Three Cepheid variable stars, pulsating stars used to measure distance and age of objects, are visible in this view of the heart of the Milky Way. This image was taken using the South African Astronomical Observatory and released Aug. 24, 2011.
CREDIT: N. Matsunaga

View full size image

When these three pulsing stars formed, the bulge of the Milky Way was churning out approximately 0.075 solar masses per year.

The lack of older pulsing stars implied that, overall, less stars were forming 30 million to 70 million years ago. If more stars were created, then more Cepheids would have been seen. Matsunaga's calculations put the rate of star formation at 0.02 solar masses a year.

"Stars are formed more actively in a region with more massive and more dense gas," Matsunaga said.

"Therefore, the change in star formation rate suggests that the gas density in the bulge was higher 25 million years ago."

He went on to explain that other research reveals that different formations within a galaxy could lead to random inflows of gas, which would fuel star formation.

Such an inflow seems to have occurred 20 million to 30 million years ago, bolstering the rate at which stars are created.

Understanding these inflows provides astronomers with a better idea of how the Milky Way evolved, and what it may do in the future.

Article From Livescience.

Hillary Maruwa August 26th, 2011

Monkeys...

Amazon Expedition Discovers New Monkey

The researchers discovered what appears to be a new species of Callicebus, or titi, monkey, with unique features on its head and tail. CREDIT: © Julio Dalponte View full size image

A possible new species of monkey has been discovered during an expedition in an unexplored part of the Amazon in mid-western Brazil.

A specimen, which scientists know is a type of Callicebus, or titi, monkey has been turned over to experts at the Emílio Goeldi Museum in the Brazilian state of Para, where it will be studied and formally described. [Amazon Expedition: An Album]

"This primate has features on its head and tail that have never been observed before in other titi monkey species found in the same area," said Julio Dalpone, the biologist who discovered the monkey during the World Wide Fund for Nature-backed expedition.

The expedition found the monkey between the Guariba River and the Roosevelt River in the northwestern part of the Brazilian state of Mato Grosso.

The 20-day expedition undertaken in December of 2010 explored four protected areas of the Guariba-Roosevelt Extractive Reserve, the Tucumã State Park and the Roosevelt River and Madeirinha River. It was intended to gather information to improve the management of these areas.

The team found 48 species of mammal, including armadillos, anteaters, deer and monkeys, as well as 313 species of birds, including some that had only previously been seen in other South American countries. Their survey of fish turned up possible new species, including a catfish, a small, brightly colored tetra, and very small fish known locally as 'piaus.' [In Amazon, New Species Discovered Every Three Days]

They also found threatened species, including a giant anteater, giant armadillo, giant otter, jaguar and ocelot.

The area explored faces a litany of environmental and social problems, including illegal logging and fishing, pollution, the expansion of agriculture, violent conflicts over land, a lack of health or education services and electricity, plus a lack of oversight by state and federal authorities, according to the WWF.

Article from Livescience.
Hillary Maruwa August 26th, 2011

To amp up your brain health and slow cognitive decline

Foods that are good for your Brain

Foods high in compounds such as antioxidants and omega-3 fatty acids can improve brain health and memory, experts say.

From fruit to fish, here are six things that, based on various studies, may perk up your gray matter.

Credit: Andrzej Gdula | Stock Xchng

Walnuts

They even look like little brains, so maybe that's Mother Nature's way of telling us what walnuts are good for.

Indeed, a 2009 study in the Journal of Nutrition found that diets in which nuts made up as little as 2 percent reversed signs of aging in the brains of old rats, including the ability of the brain to function and process information.

And a study presented in 2010 at the International Conference on Alzheimer's Disease reported that mice with Alzheimer's demonstrated improved learning, memory and motor coordination after being fed walnuts.

Walnuts contain high amounts of antioxidants, which some researchers say may combat the damage to brain cells' DNA caused by free radicals in our bodies.

Credit: Kata Szikora | Stock Xchng

Carrots

Carrots have long been known to be good for the eyes — and it turns out, they're good for the brain, too.

Carrots have high levels of a compound called luteolin, which could reduce age-related memory deficits and inflammation in the brain, according to a study published in 2010 in the journal Nutrition. In the study, mice whose daily diet was  supplemented with 20 milligrams of luteolin had reduced inflammation in their brains. The researchers said the compound also restored the mice's memory to the level of younger mice's.

Olive oil, peppers and celery are also high in luteolin.

Berries

Adding some vitamin-rich berries to your diet may not be a bad idea if you want to improve your memory, according to several studies.

One study, published in 2010 in the Journal of Agricultural and Food Chemistry, found that after 12 weeks of daily supplements of wild blueberry juice, nine older adults who had started to experience slight memory problems showed better learning and recall abilities than a similar group of adults who didn't take the supplements. The blueberry group also showed reduced symptoms of depression.

And in a 2009 report in the Journal of Nutrition, researchers said they examined a group of studies that showed fruits such as blueberries and strawberries, which are high in antioxidants, can decrease a type of stress in cells associated with aging and increase the signaling capabilities in brains. In one of the studies, researchers placed 6-month-old rats on a diet supplemented with blueberry and strawberry extracts (totaling 2 percent of their diet) for nine months. These rats had better spatial and memory skills than rats not given the supplements.

Fish

Although recent research has shown that taking fish oil supplements may not help slow the cognitive decline in people with Alzheimer's disease, other studies have shown that eating fish rich in omega-3 fatty acids could help slow typical cognitive decline that comes with age.

A 2005 study in the journal Archives of Neurology found that people 65 and older who ate two meals of fish a week for six years had a 13 percent decrease in cognitive decline, compared with people who didn't eat any fish regularly. And people who ate one meal of fish a week had a 10 percent decrease in cognitive decline.

Fish high in vitamin B12 may also help protect against Alzheimer's, according to a study published in 2010 in the journal Neurology.

Credit: Debbie Schiel | Stock Xchng

Coffee and tea

Coffee and tea do more than keep you awake in the mornings — studies have shown they may prevent Alzheimer's disease and improve cognitive function.

A 2010 study in the Journal of Alzheimer's Disease found that when researchers gave caffeinated coffee to mice genetically engineered to develop Alzheimer's disease, the disease either slowed in progression or never developed. Based on the finding, coffee eventually could serve as a therapeutic treatment for people with Alzheimer's disease, the researchers said.

Tea showed protective effects on the brain, too. Tea drinkers did better on tests on memory and information processing than non-tea drinkers did, according to a 2010 study of 716 Chinese adults 55 and older in the Journal of Nutrition, Health and Aging.

Credit: Andreas Andersson | Stock Xchng

Spinach

Your mom always told you to eat your spinach, and there's science to back up her advice. The green leafy vegetable is loaded with vitamins C and E, which, studies have shown, help to improve cognitive abilities.

A 2000 study in the Journals of Gerontology showed that rats whose diet was supplemented with vitamin E experienced a 500 to 900 percent increase in brain and nerve tissue over an eight-month period, as well as an increase in the release of dopamine in the brain, the "pleasure" chemical that controls flow of information to different parts of the brain.

And a 2000 study in the journal Brain Research found that aging rats had some of their age-related memory and motor deficits reversed after they were fed diets supplemented with spinach, strawberries or blueberries.

Article from Live Science.
Hillary Maruwa Aug 19th, 2011

Brain Image Album

Inside the Brain: A Journey Through Time

The Human BrainCredit: © Benjamin Albiach Galan | Dreamstime.comThe brain has long boggled the mind with its complexity, which is probably best summed up by Carl Sagan in "The Cosmos," when he said, "The brain is a very big place in a very small space." With modern technology, scientists are peering deeper and closer than ever before at the tangle of neurons and their billions of connections. Here's a peek at what the brain looks like, from antiquity to present-day.

Portraits of the MindCredit: Thomas Deerinck and Mark Ellisman, 2004.In the book, "Portraits of the Mind: Visualizing the Brain from Antiquity to the 21st Century" (Abrams 2010), astonishing images that reveal both the complexity and beauty of the brain. And through time as brain-imaging technology comes online, scientists have new ways of seeing and interpreting the brain. Check out some of the amazing photos from the book.

Canine ScentsCredit: Camillo GolgiThis 1875 drawing showing a dog's olfactory bulb was completed using a staining method named after Camillo Golgi in which certain chemicals are injected into nervous tissue so they can be seen. Some say its application to the study of brain tissue represents the beginning of modern neuroscience.

Dripping DendritesCredit: In-Jung Kim and Joshua Sanes, 2008.

While all cells in the body hold the same genome, only a particular set of its genes get turned on in various cells; each type of neuron switches on a gene set that defines its character.
In this picture, a gene called JAM-B had been switched on, which then turned on a fluorescent protein to reveal a small group of brain cells. The resulting image shows that all of the neurons' projections called dendrites are aligned in the same direction; moreover, these retinal neurons are known to detect only objects moving in an upward direction.

Baroque Blood VesselsCredit: Alfonso Rodríguez-Baeza and Marisa Ortega-Sánchez, 2009.A scanning electron microscope (SEM) image zooms in on the baroque branching structures that send blood to the human brain's cortex. The vessels are organized such that the large blood vessels surround the surface of the brain (top of image), sending thin, dense projections down into the depths of the cortex (bottom of image).

View of a StrokeCredit: Henning U. Voss and Nicholas D. Schiff, 2008.A brain-imaging method called diffusion MRI (magnetic resonance imaging) is relatively new to the field of neuroscience, though it shows promise as a diagnostic tool. Here, an image taken from the brain of a patient who suffered a stroke in the thalamus and midbrain, resulting in damage to certain axons (some are visible at the bottom of the image).

Mouse BrainCredit: Tamily Weissman, Jeff Lichtman, and Joshua Sanes, 2005.A cross-section of a mouse's hippocampus — one of the brain's memory centers — reveals its intricate network of neurons, whose soma are shown as small circles. The hippocampus is seen here nestled directly beneath the neocortex, which is the outer layer of the cerebral hemispheres.

Spiny NeuronCredit: Thomas Deerinck and Mark Ellisman, 2009.Most neurons have three parts: an axon, a cell body called a soma and dendrites. This scanning electron microscope (SEM) image shows a soma with dendrites (and their spines) radiating from it. To create SEM images, a beam of electrons is scanned across the surface of a sample, and a detector keeps track of electrons bouncing off its surface to reveal the specimen's outer shape.

Artsy Brain CellsCredit: Thomas Deerinck and Mark Ellisaman, 2004.Here, two types of cells in the cerebellum are shown: glia and Purkinje neurons. The cells can be distinguished because of a method that relies on the body's immune system and its antibodies — proteins that recognize and latch onto "foreign substances." Biologists now use antibodies to reveal where certain proteins are found in the brain. Here, red is an antibody staining of a protein that's found in glia cells, while green reveals a protein called IP3, of which Purkinje neurons are chockfull.

Color My CerebellumCredit: Tamily Weissman, Jeff Lichtman, and Joshua Sanes, 2007The colored splotches reveal so-called presynaptic terminals, or junctions through which neuron signals are sent, formed by the cerebellum's axons.

BrainbowCredit: Ryan Draft, Jeff Lichtman, and Joshua Sanes, 2007.

While Golgi's staining method did wonders for finding structures hidden in a tangle of neurons, it couldn't distinguish individual brain cells that were illuminated in the same color.
Enter a bit of genetic trickery called Brainbow: Robert Tsien and other chemists tinkered with and discovered fluorescent proteins responsible for the different colors emitted by various sea creatures (such as corals and jellyfish). By coaxing different sets of neurons or even different individuals of a species (say a male and female) to express different proteins, scientists could pick out the cells by the color they glowed.
Here, several motor-neuron axons (slender projections on neurons that transmit signals to other neurons) travel side by side as they lead to the muscles whose contractions they regulate.

Article from Live Science.

Hillary Maruwa Aug 19Th, 2011

Flaxseed may mitigate the effects of radiation exposure.

Flaxseed Might Protect Against Death from Radiation

Credit: Monica Armstrong | Dreamstime View full size image

Flaxseed may protect against the damaging effects of radiation, whether from a terrorist's dirty bomb or a routine cancer treatment, a new study in mice suggests.

Mice that ate flaxseed either before or up to six weeks after receiving a large radiation dose to the chest were more likely to survive and had fewer lung problems than mice not given flaxseed. Four months after receiving radiation, up to 88 percent of mice that ate flaxseed were still alive, compared with just 40 percent of mice who did not eat flaxseed.

Researchers have been particularly interested in finding a cheap, safe supplement to give to people who have been exposed to radiation in the event of a terrorist attack.

"You need to give something that's really safe as well as [easy] to deliver to a huge number of people all at once," said study researcher Dr. Keith Cengel, an assistant professor of radiation oncology at the University of Pennsylvania School of Medicine. Flaxseed meets these requirements and may provide additional health benefits, including improved heart health. "It’s as close to a no-brainer as you get," Cengel said.

However, the researchers are not certain the protective benefits will translate to people.

The new study was published online in the journal BMC Cancer on June 24.

Radiation dangers

Terrorist use of a "dirty bomb" could expose large numbers of people to radiation. This type of bomb disperses radioactive material in the form of an aerosolized powder, and poses great health risks, the researchers said. One type of lung injury that can follow is called fibrosis, in which scar tissue prevents the lung from being able to expand normally during breathing. This injury can also occur in lung cancer patients who have received too much radiation during treatment. 

The mice in the new study received a single dose of radiation equivalent to getting about 10,000 X-rays, or what a cancer patient might receive over an entire course of radiation treatment, Cengel said.
One group of mice ate a diet of 10 percent flaxseed before radiation. In people, this would be the equivalent of eating four tablespoons of whole-grain flaxseed per day, the researchers said. Other mice were given that amount of flaxseed two, four or six weeks after radiation. A control group ate no flaxseed.

Aside from having a better chance of surviving, the mice that ate flaxseed also lost less weight and had a  lower risk of inflammation and fibrosis than those who didn't eat flaxseed.

The researchers said they aren't sure how flaxseed mitigates radiation's effects. Most DNA damage occurs immediately after a radiation exposure, but flaxseed may prevent the body from reacting in an abnormal way to the radiation, and thus causing further damage, Cengel said.

What about people?

"This is extremely encouraging," Dr. Nagy Elsayyad, an assistant professor of radiation oncology at the University of Miami Sylvester Comprehensive Cancer Center, said of the study's results. The results warrant more research in this area, said Elsayyad, who was not involved with the study.

It's possible providing flaxseed to lung cancer patients before radiation treatment could allow doctors to increase the radiation dose without increasing the risk of injury, Elsayyad said. "That could translate to better cure rates with radiation," he said.

But some are skeptical about whether flaxseed could be used after a terrorist attack or nuclear accident.

"I think there's a likelihood it might do some good," said Dr. Jacqueline Williams, a radiation expert at the University of Rochester in New York. "But I think what the decades of research that have gone into such attempts have shown is that a single drug or a single attempt like this is unlikely to be totally effective," Williams said. It's more likely a combination of agents will be needed to provide protection, she said.

And the mice used in the study were genetically identical, in contrast to people, who are genetically diverse, Williams said. It's unclear whether flaxseed would have the same effect on everyone, she said.

The researchers are now testing the effectives of flaxseed to prevent radiation damage in people receiving radiation treatments for cancer, Cengel said.

Article from Livescience.

Hillary Maruwa August 15th, 2011

Glowing Necklace in Space

Hubble Telescope Finds Glowing 'Necklace' in Space

The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta (the Arrow). This composite image was taken on July 2, 2011 by the Hubble Space Telescope's Wide Field Camera 3. CREDIT: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) View full size image

Talk about bling! A giant "necklace" glowing brightly in space is the centerpiece of a new photo from NASA's Hubble Space Telescope.

The cosmic object, which is appropriately named the Necklace Nebula, is a recently discovered planetary nebula, made up of the glowing remains of an ordinary, sun-like star. The Necklace Nebula is located about 15,000 light-years away in the constellation Sagitta.

Planetary nebulas form when stars similar to our sun deplete their store of hydrogen fuel. The stars' outer layers expand and cool, creating a massive envelope of dust and gas. Radiation flowing out from the dying star ionizes this envelope, causing it to glow. [See Hubble's photo of the Necklace Nebula]

Despite the implications of their name, planetary nebulas have nothing to do with planets. Rather, the term refers to their apparent resemblance to giant planets when they were observed through early telescopes.

The Necklace Nebula consists of a bright ring, measuring 12 trillion miles (more than 19 trillion kilometers) wide. The dense, luminescent knots of gas around the ring resemble the necklace's jewels. [50 Deep Space Nebula Photos]

A pair of stars orbiting close to one another produced this nebula, which is formally known as PN G054.2-03.4. About 10,000 years ago, one of the aging stars ballooned until it engulfed its companion star. The smaller star, though consumed, continued orbiting inside its larger companion, increasing the more massive star's rotation rate.

As a result, the bloated companion star spun so fast that a large part of its gaseous envelope expanded into space. Due to centrifugal force, most of the escaping gas seeped out along the star's equator, producing a ring. The embedded knots are densely packed clumps of gas in the ring.

The stars in the pair are so close — only a few million miles apart, they appear as one bright dot in the center of the ring. The stars are whirling so furiously around each other that they complete a full orbit in a little more than a day.

Article from Live Science.
Hillary Maruwa August 15th, 2011

Lions Kill and Go Away, to Kill Again Another Day

 

A lioness leaving an elephant carcass; researchers have found lionesses often leave the scenes of their crimes since prey are likely on high alert. CREDIT: Stéphanie Périquet View full size image

Lions apparently flee the scenes of their crimes, withdrawing after successful kills while other potential prey are still on high alert, researchers have found by using satellites to track some of the deadly African cats.
This research into the minds of lions sheds light on why and when large predators move on from one hunting ground to the next, a crucial decision when the stakes are survival or starvation. In turn, such insights could lead to better designs of protected areas for African lions, whose numbers have shrunk by half in 30 years.
Deciphering the strategies of predators is difficult enough when they are captive, not to mention when they are free to range far in the wild.

"Such fieldwork is time-consuming, difficult and potentially dangerous," said researcher Marion Valeix, an ecologist at the University of Oxford in England and the French National Center for Scientific Research.
Scientists have had two ideas regarding why large mammalian carnivores depart a hunting ground. In the "unsuccessful hunt" hypothesis, predators hunt everything they can and then move on. In the alternate "patch disturbance" hypothesis, hunters leave after a successful kill to give remaining prey time to lower their guard — allowing the predators to return and blindside them. [Lions Attack Humans When Full Moon Wanes]
To see which strategy lions adopted, researchers followed the movements of eight African lions wearing global positioning system collars and ranging over about 2,700 square miles (7,000 square kilometers) in Hwange National Park in Zimbabwe.
Scientists matched the whereabouts of these big cats with 164 lion kills tracked down between 2005 and 2007. They found that after 87 percent of kills, the lions traveled at least three miles (five kilometers) or more, suggesting they were departing the scenes of their crimes.
"We showed the need for these animals to rotate their hunting between several hunting grounds — for example, waterholes in the Hwange ecosystem," Valeix told LiveScience. "This has implications regarding the configuration and size of lion home range and needs to be taken into account in the design of small conservation reserves."
Most studies focusing on large carnivores have considered them and large herbivores to be rather static variables.
"The most important implication of our findings is that they make a strong case for the crucial need to consider the behavior of large carnivores and large herbivores in a dynamic framework — lions continuously adjust to the behavior of their prey, which continuously adjust to the whereabouts of their predators."
In the future, the scientists plan to study both the behavior of predator and prey at the same time. They detailed their new findings in the August issue of the journal American Naturalist.

Article from Live Science.