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So, I'm pretty sure I've mentioned it here before. But similar to the Great Red Spot on Jupiter, Saturn has a huge storm at its north pole, that's 4 times the size of the Earth. The storm has been swirling for as long as we've been able to see it. And it's shaped like a hexagon.
NASA's Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn's north pole.
This is the first hexagon movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.
"The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. "A hurricane on Earth typically lasts a week, but this has been here for decades -- and who knows -- maybe centuries."
Weather patterns on Earth are interrupted when they encounter friction from landforms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas.
Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012. Cassini captured images of the hexagon over a 10-hour time span with high-resolution cameras, giving scientists a good look at the motion of cloud structures within.
They saw the storm around the pole, as well as small vortices rotating in the opposite direction of the hexagon. Some of the vortices are swept along with the jet stream as if on a racetrack. The largest of these vortices spans about 2,200 miles (3,500 kilometers), or about twice the size of the largest hurricane recorded on Earth.
Scientists analyzed these images in false color, a rendering method that makes it easier to distinguish differences among the types of particles suspended in the atmosphere -- relatively small particles that make up haze -- inside and outside the hexagon.
"Inside the hexagon, there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true," said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Virginia. "The hexagonal jet stream is acting like a barrier, which results in something like Earth's Antarctic ozone hole."
The Antarctic ozone hole forms within a region enclosed by a jet stream with similarities to the hexagon. Wintertime conditions enable ozone-destroying chemical processes to occur, and the jet stream prevents a resupply of ozone from the outside. At Saturn, large aerosols cannot cross into the hexagonal jet stream from outside, and large aerosol particles are created when sunlight shines on the atmosphere. Only recently, with the start of Saturn's northern spring in August 2009, did sunlight begin bathing the planet's northern hemisphere.
"As we approach Saturn's summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
A black-and-white version of the imaging camera movie and movies obtained by Cassini's visual and infrared mapping spectrometer are also tools Cassini scientists can use to look at wind speeds and the mini-storms inside the jet stream.
Cassini launched in 1997 and arrived at Saturn on July 1, 2004. Its mission is scheduled to end in September 2017. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo. [Reply]
THC appears to increase our sensitivity to scents and flavors by using naturally occurring neural networks to convince the brain that it's starving
It's one of the most well-known effects of marijuana: the powerful surge in appetite many users feel after smoking or ingesting the drug, colloquially known as "the munchies.
For medicinal users that have trouble eating due to chemotherapy, this can be one of the drug's biggest benefits. For recreational users, this benefit can also be rather enjoyable, if unkind on the waistline. But for years, scientists have struggled to understand how marijuana's active ingredient—tetrahydrocannabinol, or THC—stimulates appetite.
A new study published today in Nature Neuroscience brings us a bit closer to solving the mystery. A team of European neuroscientists led by Giovanni Marsicano of the University of Bordeaux has found that, in mice, THC fits into receptors in the brain's olfactory bulb, significantly increasing the animals' ability to smell food and leading them to eat more of it. A big part of the reason why you might eat more food after using marijuana, the research indicates, is simply that you can smell and taste it more acutely.
This effect of THC has to do with the underlying reason why the chemical affects the human brain so potently in the first place. Likely produced by the marijuana plant as a self-defense against herbivores who might feel disorientated after eating the plant and avoid it in the future, THC fits into receptors that are part of the brain's natural endocannabinoid system, which helps to control emotions, memory, pain sensitivity and appetite. Our brains typically produce their own chemicals (called cannabinoids) that fit into these same receptors, so by mimicking their activity, THC can artificially alter the same factors in dramatic ways.
The scientists began by exposing mice (increasingly used in neuroscientific research because of the surprising amount of cognitive similarities they share with humans) to banana and almond oils as a test of sensitivity to scent. When they did so, the mice sniffed the oils extensively at first, then stopped showing interest in them, a well-known phenomenon called olfactory habituation. Mice that were dosed with THC, however, kept on sniffing, demonstrating an enhanced sensitivity to the scents. These THC-dosed mice also ate much more chow when given the chance, showing an increased appetite.
The researchers also genetically engineered some mice to lack a type of cannabinoid receptor in their olfactory bulbs and subjected them to the same experiment. They found that even if these mice were given THC, it had no effect: They still habituated to the scent, showing that the drug's scent-enhancing powers involved activity in this region of the brain. In addition, these mice did not demonstrate an increased appetite when given the drug, showing that the "munchies" effect was dependent on olfactory lobe activity as well.
The upshot of all this: If mice are an accurate model for humans, one of the ways that THC increases appetite is by making us more sensitive to the smells of food. Because scent and taste are so closely related, it likely allows us to better taste flavors as well.
This new finding is likely just a piece of the THC-and-appetite puzzle. Previous research has found that the drug also acts on receptors in a region of the brain called the nucleus accumbens, increasing the release of the neurotransmitter dopamine—and the sensation of pleasure—that comes as a result of eating while high. Other work has found that THC additionally interacts with the same sorts of receptors in the hypothalamus, leading to release of the hormone ghrelin, which stimulates hunger.
The one aspect that ties together these disparate mechanisms is that they all involve the brain's natural endocannabinoid systems. THC—and, by consequence, marijuana—does much of its work by manipulating the same pathways that the brain uses to normally regulate the senses.
But perhaps most interesting is that the new study hints at a compelling metaphor for the way THC manipulates this natural system: it mimics sensations felt when we're deprived of food. As a final test, the researchers forced some mice to fast for 24 hours, and found that this drove up levels of natural cannabinoids in the olfactory lobe. Not surprisingly, these starved mice showed greater scent sensitivity and ate much more too.
Most intriguing, the genetically engineered mice with olfactory lobes that lacked cannabinoid receptors did not show increased scent sensitivity or appetite even when they were starved. This indicates that both THC and the natural cannabinoids that result from starvation are acting on the same neural pathway to allow us to smell and taste with greater sensitivity, and thus eat more. In other words, THC appears to give us the munchies by convincing our brains that we're starving. [Reply]
Originally Posted by mr. tegu:
Turks and Caicos. Specifically Grace Bay. Amazing white sand beaches there as well.
Holy hell, I just Googled it. Incredible.
In my opinion, though, nothing beats Tahiti, Bora Bora and those other islands in French Polynesia. I hope I can make it out there to experience them one day.
My 6 year-old daughter loves the movies "The Time Machine (1960)","Angry Red Planet", "First Men in the Moon", and quite a few other old Sci-Fi movies.
It's awesome. Her imagination is off the charts, and it will serve her well in the future. [Reply]
Originally Posted by ThaVirus:
Holy hell, I just Googled it. Incredible.
In my opinion, though, nothing beats Tahiti, Bora Bora and those other islands in French Polynesia. I hope I can make it out there to experience them one day.
Yeah those look amazing. I would definitely love to go there, as I am sure most would. I don't even want to know the cost though. That water is ridiculous and the scenary amazing. [Reply]
CNN) -- The presence of water on Mars is often talked about in the past tense -- as in, billions of years in the past. But researchers have found clues that water could be flowing in the present, at least during warm seasons. Researchers at Georgia Institute of Technology are looking at dark features on Martian slopes that are finger-shaped. They appear and disappear seasonally.
These flows represent the best suggestion we know of that Mars has water right now, scientists say. The study is published in the journal Geophysical Research Letters. [Reply]
A group of researchers from Penn State have pushed the realm of possibilities for nanotechnology further as they have successfully steered a nanomotor inside of a human cell. This is the first time this feat has been accomplished. The team of chemists, biologist, and engineers was led by Tom Mallouk and has been published in Angewandte Chemie International Edition.
Nanomotors have been studied in vitro more more than a decade now. The hope is that eventually, they could be used inside of human cells for biomedical research. This nanotechnology could revolutionize drug delivery and even perform surgery in order to increase quality of life in the least invasive way possible. The earliest models were nonfunctional in biological fluid due to their fuel source. A huge breakthrough came later when the nanomotors were able to be powered externally via acoustic waves. The nanomotors used inside the human cells for the latest study were controlled by the ultrasonic waves as well as magnets.
The researchers used HeLa cells, derived from a long-lived line of cervical cancer cells, to study the nanomotors. Getting past the cell membrane was easy, as the cells ingested the nanomotors themselves. Once inside, the ultrasound was turned on and the nanomotors began to spin and move around the cell. If the signal was turned up even higher, the nanomotor can spin like a propeller, chopping up the organelles inside the cell. They were even able to puncture the cell membrane, finishing off the death sentence. Used at low powers, the nanomotor was able to move around the cell without causing any damage.
The addition of magnets gave an important advantage: steering. The motors are also able to be controlled individually, allowing the operator to take a much more targeted approach to killing diseased cells.
Ultimately, the researchers hope that one day the rocket-shaped gold nanorods will be able to move in an out of the cells without causing damage. The individual units could communicate with one another to target disease in the body, maximizing the efficacy of the treatment or even making the correct diagnosis. Working toward the goal of creating such advanced nanotechnology will not only push the boundaries of nanoengineering, but will increase our understanding of chemical and biological processes at the cellular level as well.
“The assembly of a rotating HeLa cell/gold rod aggregate at an acoustic nodal line in the xy plane. The video was taken under 500X overall magnification except for 00:23 - 00:32 and 01:16 - 01:42, where a 200X overall magnification was used.” Credit: Mallouk Lab, Penn State
“Very active gold nanorods internalized inside HeLa cells in an acoustic field. A demonstration of very active gold nanorods internalized inside HeLa cells in an acoustic field. This video was taken under 1000X magnification in the bright field, with most of the incoming light blocked at the aperture.” Credit: Mallouk Lab, Penn State [Reply]
