Tasty Treats
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Rare Nacreous Clouds
Also called polar stratospheric clouds or mother of pearl clouds, nacreous clouds are mostly visible within two hours after sunset or before dawn. They blaze unbelievably bright with vivid, iridescent colors. These clouds are rare and occur in the polar stratosphere at altitudes of 15,000–25,000 meters. They are so bright because at those heights, they are still sunlit.
Although incredibly beautiful, they have a negative impact on our atmosphere. They create ozone holes by supporting chemical reactions that produce active chlorine which catalyzes ozone destruction.
(via scinerds)
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Scientists Report First Success in Cloning Human Stem Cells
It’s been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic stem cell lines from human skin cells.
Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking – could humans be cloned in the same way? Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.
Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state. The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body’s tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.
Nuclear transfer involves inserting a fully developed cell – in Mitalipov’s study, the cells came from the skin of fetuses – into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm. After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor. In Dolly’s case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isn’t designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.
“I think this is a really important advance,” says Dieter Egli, an investigator at the New York Stem Cell Foundation. “I have a very high confidence that versions of this technique will work very well; it’s something that the field has been waiting for.” Egli is among the handful of scientists who have been working to perfect the technique with human cells and in 2011, succeeded in producing human stem cells, but with double the number of chromosomes. In 2004, Woo Suk Hwang, a veterinary scientist at Seoul National University, claimed to have succeeded in achieving the feat, but later admitted to faking the data. Instead of generating embryonic stem cell lines via nuclear transfer, Hwang’s group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.
(via astro-stoner)
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(via masterandpets)
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Time for a science-tastic, carboniferous Episode Extra™ to accompany my latest YouTube vid!
In the most recent episode of It’s Okay To Be Smart on YouTube, about how we all share the same air, the #1 question from People Who Are Watching was about a number I mentioned in the beginning: We hoomanz are emitting 33-34 billion tons of CO2 a year. If the atmosphere is so dang big, is that amount of CO2 a lot?
A few people were subsequently all “Wait a sec, is Joe referencing climate change here?! Rabble rabble rabble!!!” Congrats. You caught me. Guilty as charged. But there’s science on my side, and you know what they say about science:
Where the carbon comes from: the primary people-caused CO2 sources are fossil fuels, deforestation, and cement production. Since 1850, over one thousand billion (AKA “a trillion”) tons of CO2 have been added to the atmosphere. We put about 34 billion tons of CO2 into atmosphere in 2011, the latest year I could find data. These are not debatable facts, minus a few decimals of statistical error. We can measure them, we have the technology.
Where does it go? Only 55% of this is removed by the oceans (dissolved CO2 and photosynthetic organisms) and the plants in our jungles and forests. Fifty years ago, as much as 60% of that CO2 would have been removed by oceans and plants. That means that not only are we increasing the amount of CO2 we emit every year, but plants and oceans (the carbon “sinks”) can’t keep up with the rate that we are adding it to the atmosphere.
Sure, as more carbon is put into atmosphere, plants and plankton can reproduce and take more of it up. But if we pump it out faster than they proliferate, it’s still a net loss. Oceans might actually be less able to absorb CO2 as the world warms (it’s simple chemistry, think about warm carbonated soda).
Then we get to the warming part. CO2 makes up less than one tenth of one percent of Earth’s atmosphere. So it can’t be that big of a deal to increase that by like 0.01% right? Wrong. Sure, for every million molecules of air, only ~391 of them will be CO2, but carbon dioxide is an amazingly powerful molecular mirror for solar energy, reflecting it back down to Earth and heating our planet. The math is complex, but tenths of tenths of percent changes in CO2 concentrations can lead to full degree changes in global temperatures. This doesn’t even include the effects of methane, which is almost 1,000 times less abundant as CO2, but contributes a whopping 1/5th of greenhouse gas effects.
For more: A paper in PNAS about carbon emissions and carbon sinks. A summary of emissions, warming and greenhouse gases from NOAA. Finally, you might need this: How to talk to a climate skeptic.
We do share the same small atmosphere, just like the video says. So keep it clean, because it’s mine too, dammit! (PS - If you read this far, you should totally subscribe)
(via thescienceofreality)
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(via cutecunts)
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(via masterandpets)
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