Found 5,534 Resources containing: Life science
Atomic Energy Commission exhibit featuring a presentation of the Life Science Radiation Laboratory at the Museum of History and Technology, now known as the National Museum of American History.
NASA transferred this model to the Museum in 2004.
NASA transferred this model to the Museum in 2004.
John Dee, born on this day 490 years ago, was Queen Elizabeth I’s scientific advisor–but he was also a magician.
He carried on a lengthy conversation with spirits. But he was also a Cambridge-educated scientist who did postgraduate work with the likes of Gerardus Mercator, a cutting-edge mapmaker in a time where maps were–as today–essential technology. He was an authority on navigation who was “intimately involved in laying the groundwork for several English voyages of exploration,” writes Encyclopedia Britannica. He even suggested that England should adopt the Gregorian calendar.
In 2017, these different roles might be played by totally different branches of government. “Dee is more or less uncategorisable by today’s standards,” writes Philip Ball for New Scientist. “Some of his Tudor contemporaries might have considered him a philosopher, an astrologer, perhaps even a magician–but they would have agreed that he was, above all, a mathematician.” Technically, that was the role he played at Queen Elizabeth’s court.
“And what did Dee do with math? He cast horoscopes, practiced numerology and alchemy, and sought occult codes that would permit conversations with angels in the language used by Adam,” writes Ball. Queen Elizabeth relied on him for astrology as well as for his other skills. Being court mathematician was inextricably entwined with the role of court magician (although that wasn’t a title he or anyone else held during the Elizabethan age.)
“The magic and alchemy he practiced, while never uncontroversial, were intimately woven together with his investigations into religion, mathematics and natural science,” writes Tim Martin for The Telegraph. Dee was a scientist who used the tools at his disposal to investigate the world around him, just like his contemporaries Francis Bacon–originator of the modern scientific method–and Galileo Galilei.John Dee performs an experiment in front of Queen Elizabeth I in this nineteenth-century painting. (Wellcome Library)
Dee did most of his work at his home in a river district called Mortlake, where he kept a collection of more than 4,000 books–bigger than the libraries of Oxford and Cambridge, writes Martin. With subjects ranging from mathematics and poetry to religion and astronomy, the collection was as varied as his professional pursuits. He also possessed a collection of magical artifacts, such as a magic mirror used for communicating with spirits and a crystal ball.
And this was...kind of normal for the period. “The occult sciences enjoyed a kind of Renaissance in later Elizabethan England as print and translation made ancient, medieval and earlier Renaissance texts available to would-be English adepts,” writes academic Paul S. Seaver. John Dee, like other scientific minds of the period, engaged with the occult as a way of gaining more information about the world–a world in which spirits were potentially as real as gravity. The empirical worldview of Francis Bacon “may ultimately have triumphed,” he writes, “but in the last decades of the sixteenth century, it was not at all evident that the future did not belong to those following in the footsteps of Dr. John Dee, mathematician, astrologer, alchemist, cartographer, and magus.”
Orig. negative: 11x14, Safety, BW.
Eggers and Higgins.
Black-and-white study print (11x14).
Orig. negative: 11x14, Safety, BW.
Eggers and Higgins.
Modern archeologists, excavating ancient Egyptian tombs, have often found something unexpected amongst the tombs’ artifacts: pots of honey, thousands of years old, and yet still preserved. Through millennia, the archeologists discover, the food remains unspoiled, an unmistakable testament to the eternal shelf-life of honey.
There are a few other examples of foods that keep–indefinitely–in their raw state: salt, sugar, dried rice are a few. But there’s something about honey; it can remain preserved in a completely edible form, and while you wouldn’t want to chow down on raw rice or straight salt, one could ostensibly dip into a thousand year old jar of honey and enjoy it, without preparation, as if it were a day old. Moreover, honey’s longevity lends it other properties–mainly medicinal–that other resilient foods don’t have. Which raises the question–what exactly makes honey such a special food?
The answer is as complex as honey’s flavor–you don’t get a food source with no expiration date without a whole slew of factors working in perfect harmony.
The first comes from the chemical make-up of honey itself. Honey is, first and foremost, a sugar. Sugars are hygroscopic, a term that means they contain very little water in their natural state but can readily suck in moisture if left unsealed. As Amina Harris, executive director of the Honey and Pollination Center at the Robert Mondavi Institute at Univeristy of California, Davis explains, “Honey in its natural form is very low moisture. Very few bacteria or microorganisms can survive in an environment like that, they just die. They’re smothered by it, essentially.” What Harris points out represents an important feature of honey’s longevity: for honey to spoil, there needs to be something inside of it that can spoil. With such an inhospitable environment, organisms can’t survive long enough within the jar of honey to have the chance to spoil.
Honey is also naturally extremely acidic. “It has a pH that falls between 3 and 4.5, approximately, and that acid will kill off almost anything that wants to grow there,” Harris explains. So bacteria and spoil-ready organisms must look elsewhere for a home–the life expectancy inside of honey is just too low.
But honey isn’t the only hygroscopic food source out there. Molasses, for example, which comes from the byproduct of cane sugar, is extremely hygroscopic, and is acidic, though less so than honey (molasses has a pH of around 5.5). And yet–although it may take a long time, as the sugar cane product has a longer shelf-life than fresh produce, eventually molasses will spoil.
So why does one sugar solution spoil, while another lasts indefinitely? Enter bees.
“Bees are magical,” Harris jokes. But there is certainly a special alchemy that goes into honey. Nectar, the first material collected by bees to make honey, is naturally very high in water–anywhere from 60-80 percent, by Harris’ estimate. But through the process of making honey, the bees play a large part in removing much of this moisture by flapping their wings to literally dry out the nectar. On top of behavior, the chemical makeup of a bees stomach also plays a large part in honey’s resilience. Bees have an enzyme in their stomachs called glucose oxidase (PDF). When the bees regurgitate the nectar from their mouths into the combs to make honey, this enzyme mixes with the nectar, breaking it down into two by-products: gluconic acid and hydrogen peroxide. “Then,” Harris explains, “hydrogen peroxide is the next thing that goes into work against all these other bad things that could possibly grow.”
For this reason, honey has been used for centuries as a medicinal remedy. Because it’s so thick, rejects any kind of growth and contains hydrogen peroxide, it creates the perfect barrier against infection for wounds. The earliest recorded use of honey for medicinal purposes comes from Sumerian clay tablets, which state that honey was used in 30 percent of prescriptions. The ancient Egyptians used medicinal honey regularly, making ointments to treat skin and eye diseases. “Honey was used to cover a wound or a burn or a slash, or something like that, because nothing could grow on it – so it was a natural bandage,” Harris explains.
What’s more, when honey isn’t sealed in a jar, it sucks in moisture. “While it’s drawing water out of the wound, which is how it might get infected, it’s letting off this very minute amount of hydrogen peroxide. The amount of hydrogen peroxide comes off of honey is exactly what we need–it’s so small and so minute that it actually promotes healing.” And honey for healing open gashes is no longer just folk medicine–in the past decade, Derma Sciences, a medical device company, has been marketing and selling MEDIHONEY, bandages covered in honey used in hospitals around the world.
If you buy your honey from the supermarket, that little plastic bottle of golden nectar has been heated, strained and processed so that it contains zero particulates, meaning that there’s nothing in the liquid for molecules to crystallize on, and your supermarket honey will look the same for almost forever. If you buy your honey from a small-scale vendor, however, certain particulates might remain, from pollen to enzymes. With these particulates, the honey might crystallize, but don’t worry–if it’s sealed, it’s not spoiled and won’t be for quite some time.
A jar of honey’s seal, it turns out, is the final factor that’s key to honey’s long shelf life, as exemplified by the storied millennia-old Egyptian specimens. While honey is certainly a super-food, it isn’t supernatural–if you leave it out, unsealed in a humid environment, it will spoil. As Harris explains, ” As long as the lid stays on it and no water is added to it, honey will not go bad. As soon as you add water to it, it may go bad. Or if you open the lid, it may get more water in it and it may go bad.”
So if you’re interested in keeping honey for hundreds of years, do what the bees do and keep it sealed–a hard thing to do with this delicious treat!
Life sciences collection
Biological abstracts 0006-3169
Chemical abstracts 0009-2258
Nuclear science abstracts 0029-5612
If you stare at one of Cornelia Hesse-Honegger’s watercolors long enough, you’ll notice something’s a little bit off with the insects she depicts. There’s a bent antennae or a crumpled wing—the deformities make it clear to the viewer that this bug is not “normal.”
“Each one is a little bit like a puzzle,” says Tim Mousseau, a biologist at the University of South Carolina. “The closer you look the more you see.”
A Zurich-based artist and scientific illustrator, Hesse-Honegger has been peering into microscopes and drawing malformed insects for decades. Her bright paintings of “true bugs”—insects like firebugs, aphids and cicadas that all share a unique sucking mouth organ—often focus on their anatomy, and look like something out of a beautiful old-school entomology textbook.
She got her start working is an illustrator at an entomology lab at the University of Zurich in the 1960s, where she drew flies and other insects that had been exposed to different mutagens, such as x-rays and ethyl methanesulfonate (a compound similar to Agent Orange). But, perhaps her most famous work comes from areas affected by the explosion at a nuclear power station in Chernobyl, Ukraine, on April 26, 1986. Knowing that severe radiation exposure can cause mutations in the string of DNA letters found within cells, and that those mutations might cause deformities in a creature’s body plan, Hesse-Honegger went looking for her preferred bugs in regions under the Chernobyl cloud, first in Sweden and then in southern Switzerland.
“All living beings in areas contaminated by the radioactive cloud were now in a situation comparable to that of laboratory flies exposed to radioactivity,” she says. And when she looked, collecting 50 to 500 insects at various locations, she did find insects with slight abnormalities in their anatomy.
When Hesse-Honegger’s images were first published in the late 1980s, though, they generated uproar and criticism in the scientific community. Most research was focused on the health risks to humans and engineering issues. Enough time hadn’t passed for scientists to understand Chernobyl’s impact on biological communities, and many thought the effects on animals and insects would probably be minor.
In 1990, she traveled to Chernobyl itself, collecting insects from within the exclusion area around the sarcophagus of the nuclear reactor. Out of the 55 true bugs she collected, 12 were malformed.
Of course, she had no way of knowing whether the abnormalities she saw were from mutations, or whether any possible mutations were caused by the radiation. Some suggested that perhaps her field samplings were statistically insignificant exceptions to the norm, simply the result of natural mutation or injury. Others claimed the work was inaccurate and unscientific. Though the nuclear explosion initially released high levels of radiation lethal to animals (including humans) and plants, in the days and months following, radiation (mainly in the form of Cesium-137, which has a half life of 30 years) would have stuck around these areas only at much lower doses.
Hesse-Honegger’s project certainly had some artistic momentum. Over the years, she has collected and drawn over 16,000 true bugs from 25 nuclear sites across the globe—and not just disaster areas, like Chernobyl and Three Mile Island. Wondering whether low doses of radiation were an issue at nuclear plants and laboratories as well, she has visited working nuclear installations, including one in La Hague, France. She even took live-samples from areas impacted by Chernobyl in Switzerland, and bred populations of flies (Drosophila melanogaster) in her kitchen to observe abnormalities in the offspring. Hesse-Honegger published these artistic studies in the journal Chemistry & Biodiversity in 2007.
But after so many years, what do scientists really know about the impact on animal life?
Mutations have been found in animal populations within the original 1,004-square-mile Chernobyl exclusion area, including in barn swallows (Hirundo rustica) and bank voles (Clethrionomys glareolus). And, a 1994 study showed increased mutation rates in flies (Drosphila subobscura) in Sweden, though in each case it’s hard to say whether Chernobyl was to blame.
A composite photograph of fire bugs found around Chernobyl collected in 2011 by Tim Mousseau and Anders Moller shows various abnormalities. (Photo: Mousseau and Moller)
Mutations caused by radionuclides (radioactive isotopes of elements) come in two forms: germline mutations in the DNA of the sperm or egg or mutations in cellular DNA due to exposure that can cause different forms of cancer. The first is passed down to future generations, and the second is typically not. Both types of mutations would likely look like mutations that arise normally in insects—so no glowing grasshoppers or giant flies of science fiction fodder are likely buzzing around Ukraine. Individual mutations probably wouldn’t impede an insect’s survival, but if new mutations accumulate in these bugs overtime, fitness could drop due to natural selection pressure.
For any animal or insect, a drop in fitness could produce negative effects at the ecological community level. Since the mid-1990s, scientists have reported that moose, boar, otter and other animal communities thrive around Chernobyl. But a string of studies since then have suggested that all might not be so idyllic for some species. Barn swallows living in the exclusion area have seen increased rates of albinism and cataracts, as well as decreased reproduction and survival.
“We have a very, very incomplete picture,” says Mousseau, who studies birds and insects around Chernobyl and Fukushima in Japan. In 2009, Mouseau and his colleagues did find lower populations of butterflies, bees, dragonflies and spiders in areas inside the 12-square-mile exclusion zone around Chernobyl compared to those further away. But, he adds, “There’s been very little research done to rigorously assess the impacts of the radioactive contaminants on the insect communities in the area.”
Scientists do know that some species might be less susceptible than others, and perhaps mutant bugs could adapt to such stressful conditions. In a Functional Ecology paper published this week, Mousseau and his colleagues revealed that some bird species living near Chernobyl might be adapting to low-dose radiation levels. As scientists discern Chernobyl’s radioactive legacy, they’re also figuring out how evolution works in a radioactive world.
The natural world is dynamic, so it’s hard to predict what Chernobyl will look like in the future. But, perhaps the abnormally formed critters that Hesse-Honegger captured will inspire future scientists to solve these ecological puzzles—as she originally hoped they would.
When the aliens arrive, they will likely seize the cell phones. And the iPods and laptops and PDAs. Not because they desire the toys, but because these devices accompany us on our walks and drives and subway rides with such little exception that, to a fresh observer, the gizmos might appear to power us.
In many senses they do. We must remember to slip them into our pockets and purses before leaving the house. More vitally, we must remember to re-charge them every evening. It's only a matter of time before that classic teenage nightmare of being naked in school is replaced by the terror of a Low Battery signal—beeping in one's pocket during Study Hall like the beating of some hideous heart.
So when can we reclaim control of our memories and dreams? When can we cut these modern umbilical cords and have gadgets that power-up wirelessly while we do more important things—like text-message our vote for the next American Idol?
Wireless transfer itself is nothing new. Radio waves have broadcast information to tiny antennas for decades. Lots of energy, in the form of radiation, is lost during these transmissions, however. That's fine for sending data such as cell phone positions, a process that requires little energy. But sending power itself requires conserving as much energy as possible during the transfer.
So, engineers need a more frugal way to send power. One option is through resonance: when one resonant object produces energy at a certain frequency, a nearby resonant object at the same frequency can suck up the power efficiently. Put simply, this type of energy transfer explains why a booming singer might cause a wine glass, filled to the right level, to vibrate visibly—perhaps even to shatter.
But unless you're married to the Fat Lady and call home using stemware, this "acoustic resonance" won't help you charge your mobile phone. Instead, engineers can harness "magnetic resonance" by designing twin coils whose magnetic fields speak to each other, in a sense, across a bedroom or café.
This wireless energy transfer requires that the two coils be set to the same frequency. Then, when one coil is connected to a power source such as a battery or outlet, it will send energy to the other coil implanted in an electronic device.
The system has several benefits. Few everyday items interact with magnetic fields, so it's unlikely for something to unintentionally drain power from the coils. Unlike a laser, resonant coils can transfer energy through obstacles, so your PC continues to charge even if someone plops a grande latte between your laptop and the wall. And because the coils are designed to conserve radiation, the devices pose no harm to people—aside from the potential to help inflate a cell phone bill.
The largest drawback is that wireless power currently works across a moderate-sized room (in one test it lighted a bulb seven feet away), but long-range transfer appears highly difficult, if not impossible. So when the aliens commandeer your Blackberry and take it back to their home planet, the joke's on them. Unless, of course, they probe you first.
The real Wishful Thinker behind this column was Aristeidis Karalis, an engineering graduate student at the Massachusetts Institute of Technology, who predicts the system might be available for products within the next several years.
Have an idea that should be thought about wishfully? Send it to firstname.lastname@example.org
"When I was a kid," says John Grant, "the big thing was: there are billions of stars in our own Milky Way, what are the odds that life doesn't exist?"
Grant, no longer a kid in stature if still in spirit, now plays a substantial role in setting those odds. The geologist at the Center for Earth and Planetary Studies, part of the National Air and Space Museum, is one of a half dozen scientists in charge of creating itineraries for Spirit and Opportunity, the two NASA rovers that since early 2004 have explored Mars for signs of life, past or present.
Researchers designed the rovers to gather images of rocks and terrain where water, the presumed prerequisite of life, might have flowed. Opportunity's success came soon after touching down at Meridiani Planum, Spirit's a while after landing among the volcanic rocks of Gusev Crater. But the rovers' life-detection skills are limited. They lack the equipment to analyze organic compounds or examine fossils. (The mission's running joke, says Grant, is that a rover will spot a dinosaur bone and be unable to retrieve it.) These tasks are reserved for the Mars Science Laboratory mission, scheduled for 2010.
The search for life in the universe, however, isn't confined to the rovers' path. For that matter, it's no longer limited to Mars, or even the Earth's solar system. More and more, astronomers at labs and observatories around the world are finding evidence for the foundations of life—foremost, water—in our planet cluster and beyond.
"As we get more data about places outside of Earth, we're starting to see conditions where you've got to scratch your head and say, 'This is a potentially habitable environment,'" says Grant. "It's not proof, but you're doing the statistics and they're all going in the category of: In Favor of Life."
That column received another check in mid June, when a group of scientists revived the idea that a vast ocean once existed on the northern hemisphere of Mars. A couple decades ago, scientists analyzed images of this region and found what seemed to be a shoreline. But an ocean shoreline has a uniform elevation, and later topographical tests revealed great variation—in some places, more than a mile separated the terrain's peaks and dips.
The new research, published in the June 14 Nature, argues that, in the past billion or so years, Mars has changed the way it spins on its axis. In the process, much of the planet's mass has shifted in a manner that accounts for the alternation of the once-level shoreline.
The ocean, of course, no longer ebbs and flows along this boundary. But it's unlikely that all the water escaped into the universe, says the study's lead author, J. Taylor Perron of Harvard University.
"We know that life, as we're familiar with it, seems to require liquid water," says Perron. "That basic requirement may have been satisfied on Mars, either when the ocean existed on the surface, or subsequently deeper within the crust."
Whether scientists can dig into the planet's surface and find evidence of water—and with it signatures of life—remains to be seen. Whether they can Massachusetts Institute of Technology, who was not associated with the study, in an accompanying commentary. "The result hints … that the understanding of the 'blue' history of the red planet is far from complete."
Image by Courtesy of Tyler Perron. This image, generated using data from surveyor spacecrafts, shows how an ocean on Mars might have appeared more than 2 billion years ago. (original image)
Image by NASA / JPL-Caltech. Since early 2004, the Mars rovers have gathered images of rocks and terrain where water, the presumed prerequisite of life, once flowed (an artist's rendition). (original image)
Image by NASA / JPL-Caltech / Cornell. This panorama, made from a compilation of Spirit's images, shows the landscape near the rover's "Winter Haven." (original image)
Image by NASA / JPL. Tidal friction causes cracks and ridges on Europa's icy surface (red lines). The red splotches indicate where ice blocks have moved around. (original image)
Image by ESO. The star Gliese 581. (original image)
Image by ESO. An Earth-like planet (foreground, artist's rendition), orbits Gliese 581 in 13 days. (original image)
Many scientists believe that the blue history of Europa, one of Jupiter's moons, is still being written. Europa circles Jupiter every few days, and this rapid orbit generates friction that heats up the moon's interior. For that reason, some feel that an enormous salty ocean still exists beneath Europa's frozen surface, containing perhaps twice as much liquid as all the Earth's oceans combined.
Though the search for life on Mars has diverted attention and resources from Europa, the icy moon offers many indications that life could thrive there, including the presence of oxygen, hydrated salt and perhaps photosynthesis. Algae, bacteria and even animals exist in similar conditions in Antarctica, often living under ice shelves.
"If we made Europa a high priority and thought carefully about where to land, I think there's a good chance we'd find signs of life there," says planetary scientist Richard Greenberg of the University of Arizona. "If there was past life on Europa, I don't see why it wouldn't still be there. It's extremely active."
Because Europa is bombarded by radiation, Earth-like organisms could not live on the surface. But they might exist just several feet below in visible cracks. In recent papers and talks, Jere Lipps of the University of California, Berkeley, has outlined several ways in which life on Europa, or its remains, might be exposed to the surface—and likewise to rovers or orbiters sent to study the moon. These include places where ice has cracked and refrozen with life trapped inside; blocks of ice that have broken off, flipped over and now face the surface; and debris lodged in ridges or deep crevices.
Such exposures mean explorations to Europa could spot life without potentially difficult landing-and-digging missions. "Europa is active in the sense that its body is continually being reshaped," says Greenberg. "Ice is cracking, opening, closing. There's a good chance that oceanic substances regularly emerge to the surface."
While Europa and other sites near Earth, such as Saturn's moon Titan, remain promising places to find water, some scientists have set their sights far beyond this solar system. Recently, Travis Barman of Lowell Observatory in Flagstaff, Arizona, detected water in the atmosphere of a planet some 150 light years away—the first such evidence for a planet outside Earth's cluster.
The planet, known as HD 209458b, resides in the constellation Pegasus and is made entirely of gas. As seen from Earth, HD 209458b passes in front of its star every few days. During this stage, the planet's atmosphere blocks a certain amount of starlight, enabling Barman to model the atmospheric components. When he compared his models to images of HD 209458b from the Hubble telescope, those that included water in the atmosphere proved accurate, he reports in the June 1 Astrophysical Letters.
A couple weeks later, a team of European researchers announced another breakthrough outside this solar system: the discovery of a planet incredibly similar to Earth. The planet, some 20 light years away and five times the mass of Earth, circles the star Gliese 581. Several years ago, scientists found another planet—this one similar to Venus—orbiting this same star.
The new planet is much closer to Gliese than Earth is to the Sun, completing its orbit in about two weeks. But because Gliese is smaller than the Sun, the temperature on this planet's surface could be amenable to liquid water, the researchers report in an upcoming issue of Astronomy & Astrophysics. "The planet is the closest Earth twin to date," they write.
In the end, though, watery conditions, or even water itself, can only tell so much of the story of life beyond Earth. The conclusion must wait until more powerful tools or more precise explorations turn mere suggestion into solid proof.
"We believe that life, as we know it, needs water to exist, but the presence of water does not imply the existence of life," says Barman. "Without some direct evidence, it will be very hard to say if life, in one form or another, is present on any planet."
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