Notable Scientist – Dr. Vera Rubin

Dr. Vera Rubin

July 1928 – December 2016

A visionary astronomer who played an instrumental role in confirming the existence of dark matter, Dr. Vera Rubin’s contributions to science will not be forgotten. A trailblazer with a passion for uncovering the unknown, she advocated for the role of women in science while expanding our understanding of the galaxy.




Blue Alien Planet Explained: Inside Hubble’s Exoplanet Color Discovery (Infographic)

Blue Alien Planet Explained: Inside Hubble’s Exoplanet Color Discovery (Infographic)

by Karl Tate, Infographics Artist
Date: 11 July 2013 Time: 09:00 AM ET
Infographic: Facts about the hot blue gas giant planet HD 189733b.

Light from the planet HD 189733b was captured by the Hubble Space Telescope and analyzed. Astronomers say that the giant planet has a deep-blue atmosphere, but conditions are in no way Earth-like.


Full Story: Strange Blue World: Alien Planet’s True Color Revealed, a First


Huge Dinosaur Tail Discovered in Mexico

Huge Dinosaur Tail Discovered in Mexico

By Laura Poppick, Staff Writer   |   July 23, 2013 12:06pm ET  via
tail of dinosaur

This is the first intact dinosaur tail to be discovered in Mexico. Fifty vertebrate of have been uncovered so far. Credit: Mauricio Marat / INAH

A giant dinosaur tail has been uncovered in northern Mexico, paleontologists announced this week.

The well-preserved tail measures about 16 feet (5 meters) long, contains 50 vertebrae, and seems to have belonged to a hadrosaur — a duck-billed dino that lived about 72 million years ago. Hadrosaurs grew to be about 40 feet (12 m) long, so the tail would have taken up just under half the length of its body.

Buried within sedimentary rock in the desert region of Coahulia, this is the first intact dinosaur tail of this size to be discovered in Mexico, and only one of a handful that has been discovered around the world, according to a statement from the Mexican National Institute for Anthropology and History (INAH). Back in 2008, archaeologists reported the discovery of another hadrosaur, dubbed Velafrons coahuilensis,found in Coahulia. That specimen likely belonged to a juvenile dinosaur; even so it the youngster would have been 25 feet (7.5 m) in length, suggesting V. coahuilensis adults grew to a whopping 30 to 35 feet (9 to 10.5 m) long. [Gallery: Gorgeous Dinosaur Fossils]

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Google’s Interactive Starmap Will Eat Your Day Whole

Google’s Interactive Starmap Will Eat Your Day Whole




Want to wave goodbye to any chance of productivity for the rest of the day? Then step right up to 100,000 Stars, an interactive starmap from those mad geniuses at Google’s Creative Lab team. The map allows you to click, scroll, and otherwise explore a (mostly) accurate representation of our cosmic “neck of the woods.” It’s gorgeous, it’s fascinating, and it will absolutely force you to cancel any meetings you had planned for the rest of the day.

Here’s Google’s official description of the map:

Visualizing the exact location of every star in the galaxy is a problem of, well, galactic proportions. With over 200 billion stars, capturing every detail of the Milky Way currently defies scientists and laptops alike. However, using imagery and data from a range of sources, including NASA and the European Space Agency (ESA), we were recently able to take one small step in that direction by plotting the location of the stars closest to our sun . . . The experiment makes use of Google Chrome’s support for WebGL, CSS3D, and Web Audio. Music was generously provided by Sam Hulick, who video game fans may recognize as a composer for the popular space adventure series, Mass Effect.

Oh Google, you already would have won my heart with the starmap alone. But then you have to take things a step further and hire the brilliant Sam Hulick to write an accompanying score? That’s just dirty pool, sir, but I love you for it.

Aside from giving you a jaw-dropping sense of scale by allowing you to zoom from an overall galactic view all the way down to our own little blue marble, 100,000 stars also provides detailed information about our interstellar neighbors. Going back to the Mass Effect tie-in again, it’s basically a way, way more detailed — and accurate — version of that game’s beautiful starmap. Just keep an eye out for Reapers while you’re seeing what’s out there.

Really, there’s nothing else I can tell you about 100,000 Stars that the map itself can’t do much more elegantly, so click on over there already. One proviso, though: you’ll need to have the Chrome browser to use the map, so click over and grab it if you haven’t already.


Ancient Temple Discovered in Peru

by LiveScience Staff
Date: 14 February 2013 Time: 02:58 PM ET

Archaeologists in Peru have uncovered what they believe is a temple, estimated to be up to 5,000 years old, at the site of El Paraíso, north of Lima.

Inside the ruins of the ancient room, which measures about 23 feet by 26 feet (7 meters by 8 meters), there’s evidence of a ceremonial hearth, where offerings may have been burned, archaeologists say. The temple also had a narrow entrance and stone walls covered with yellow clay, on which traces of red paint were found, according to a statement from Peru’s Ministry of Culture.

El Paraíso, located on the central coast of Peru, just north of Lima, is a site made up of 10 buildings stretching over 123 acres (50 hectares). It’s one of the earliest known examples of monumental stone architecture in the Americas, dating back to the Late Preceramic period (3500-1800 B.C.). The newly found building is thought to date back to 3000 B.C., which should be confirmed with a radiocarbon analysis.



The ruins of El Paraíso in Peru
CREDIT: Peru Ministry of Culture

Rafael Varón, Peru’s deputy minister for culture, said in a statement that the discovery of the temple “has particular importance because it is the first structure of this type found on the central coast.” It suggests that the Lima region had more religious, economic and political importance during this early period than previously thought, Varón added.

Previously, man-made mounds shaped like orcas, condors and even a duck were discovered in Peru’s coastal valleys, including at El Paraíso, by anthropologist Robert Benfer, professor emeritus of the University of Missouri, who spotted the mounds in satellite photos. One curious mound found in El Paraíso in the Chillón Valley was of a condor head whose burned-charcoal eye was likely the place where offerings were once burned. The condor was also positioned to line up with the most extreme orientation of the Milky Way as seen from the Chillón Valley. [See Photos of the Animal Mounds]

A second mound, right next to the condor, looked like a combination of a puma and alligatorlike cayman, Benfer said. That one was oriented toward the spot where the sun rises on the day of the June solstice, the start of summer.

Dating to more than 4,000 years ago, the structures may be the oldest evidence of animal mounds outside of North America, Benfer said last year. The previous oldest animal structures date to about 2,000 years ago, part of the Nazca Lines. These lines are simple stone outlines of animals decorating the Nazca Desert in Peru.

Follow LiveScience on Twitter @livescience . We’re also on Facebook & Google+.

Monster Black Holes Grow Surprisingly Fast

Monster Black Holes Grow Surprisingly Fast

by Mike Wall, Senior Writer
Date: 12 February 2013 Time: 07:01 PM ET
Supermassive black hole
This image depicts three hot blobs of matter orbiting a black hole. If placed in our Solar System, this black hole would appear like a dark abyss spread out nearly as wide as Mercury’s orbit. And the three blobs (each as large as the Sun) would be as far out as Jupiter. They orbit the black hole in a lightning-quick 20,000 miles per second, over a tenth of the speed of light.
CREDIT: NASA/Dana Berry, SkyWorks Digital

Giant black holes are famous for their appetites, but these matter-munching monsters are even greedier than scientists once thought, a new study suggests.

The supermassive black holes that lurk at the center of most (if not all) galaxies are growing surprisingly quickly, the study found. The result implies that these cosmic behemoths are sustained primarily by frequent small meals rather than rare and dramatic galactic mergers, as was previously believed.

Supermassive black holes are almost incomprehensibly huge, with some containing 10 billion or more times the mass of our own sun. The research team used computer simulations to investigate how such black holes grow, especially in spiral galaxies like the Earth’s Milky Way.

The astronomers found that, contrary to prevailing theory, central black holes can grow quite rapidly in quiet, merger-free spirals simply by sucking up galactic gas and other matter.

“These simulations show that it is no longer possible to argue that black holes in spiral galaxies do not grow efficiently,” study lead author Victor Debattista, of the University of Central Lancashire in England, said in a statement. “Our simulations will allow us to refine our understanding of how black holes grew in different types of galaxies.”


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The new study further bolsters the emerging view that gigantic galactic smashups are responsible for just a small portion of supermassive black holes’ growth, researchers said.

And such growth can be prodigious. The black hole at the heart of the famous Sombrero Galaxy, also known as M104 or NGC 4594, has swallowed the equivalent of one sun every 20 years and now contains at least 500 million solar masses, researchers said.

The supermassive black hole at the core of the Milky Way Galaxy appears far less greedy, growing at a rate of one solar mass every 3,000 years, researchers said. Scientists estimate that this black hole, also known as Sagittarius A* (pronounced “Sagittarius A-star”), has the mass of about 4 million suns.

The new study was published today (Feb. 12) by The Astrophysical Journal.

Follow senior writer Mike Wall on Twitter @michaeldwall  or @Spacedotcom . We’re also on Facebook and Google+

Salty Antarctic Pond May Hold Clues to Water on Mars

Salty Antarctic Pond May Hold Clues to Water on Mars

by Megan Gannon

A camera installed above Don Juan Pond in Antarctica’s McMurdo Dry Valleys took 16,000 images in two months, documenting geological processes in real time. The processes that keep Don Juan Pond liquid in Antarctica could be at work on Mars as well.
CREDIT: Geological Sciences/Brown University

Antarctica’s bizarre Don Juan Pond is the saltiest natural body of water on Earth — a distinction that keeps the little lake in a fluid state on an otherwise frozen continent.

Now researchers have found new evidence about how the pond gets enough salt to stay wet in such a hostile environment, and their study may hold clues about howliquid water might flow on Mars.

“It was a simple idea,” Brown University researcher James Dickson explained in a statement. “Let’s take 16,000 pictures of this pond over the course of two months and then see which way the water’s flowing. So we took the pictures, correlated them to the other measurements we were taking, and the story told itself.”

Those time-lapse pictures revealed that the pond’s water levels rose in step with daily spikes in temperature. This suggests modest midday snowmelt is one of Don Juan Pond’s sources of water, but it doesn’t explain where its critical salt supply comes from. [The Most Mars-Like Places on Earth]

The researchers turned another camera on channels of loose sediment around the pond known to be rich in calcium chloride salt. Whenever humidity in the air peaked, dark streaks emerged in this soil, which the researchers interpreted as water tracks formed by a process known as deliquescence. After sucking water out of the air, these salts seem to sit on the sidelines until the occasional flow of snowmelt washes them into the pond, helping to replenish the saline supply, the researchers said.

Don Juan Pond could be a stand-in for basins on the frozen desert of Mars. Scientists say that rivers and oceans may have been prominent features in the Red Planet’s early history, but any water at the surface today would have to be frozen, extremely salty, or thoroughly mixed with minerals.

The water tracks around Don Juan Pond look strikingly similar to features recently found on Mars known as recurring slope lineae. The Martian clusters of dark, narrow lines periodically appear and grow on slopes and cliff faces in the Red Planet’s warmer regions. Some scientists have taken them to be evidence of occasional flows of briny water on Marstoday.

What’s more, chloride-bearing salts have been detected on Mars, which would be capable of the same kind deliquescence seen in Antarctica, the researchers note. The new study also found that Don Juan Pond manages to stay wet without being supplied groundwater, which is not thought to exist on Mars today.

“Broadly speaking, all the ingredients are there for a Don Juan Pond-type hydrology on Mars,” Dickson said.

Scientists ultimately hope that finding water on celestial bodies such as Mars could lead to evidence for life, either past or present, beyond Earth. As the authors of the new study point out, salt-loving microbes have been discovered living just below the surface of the Atacama Desert in northern Chile, where subsoils are thought to be a good analog for dirt on Mars. And if salty basins on the Red Planet represent hydrologic systems like Don Juan Pond, “they may have significant potential for hosting resilient microbiota,” the scientists wrote, “and the most habitable places on Mars may mimic the least habitable places on Earth.”

The research was detailed online Jan. 30 in journal Nature Scientific Reports.

Follow LiveScience on Twitter @livescience . We’re also on Facebook & Google+.

Copper Sulfide Could Enable Faster Memory Chips and More Efficient Batteries

Copper Sulfide Could Enable Faster Memory Chips and More Efficient Batteries

February 11, 2013   via SciTechDaily



Artistic rendering of copper sulfide above the critical temperature at which it becomes “superionic.” Click on image for expanded view and description. Credit: Greg Stewart/SLAC National Accelerator Laboratory

A new study from SLAC and Stanford researchers examines the atomic-scale details of how superionic nanoscale materials switch from a state that is poorly conducting to one that is highly conducting, taking a step forward toward using these materials in low-cost solid-state electrical batteries.

A material that could enable faster memory chips and more efficient batteries can switch between high and low ionic conductivity states much faster than previously thought, SLAC and Stanford researchers have determined. The key is to use extremely small chunks of it.

“Our result is a step toward using this material, copper sulfide, in low-cost solid-state electrical batteries,” said the leader of the research team, Aaron Lindenberg, of the Stanford Institute for Materials and Energy Sciences and the Stanford PULSE Institute. The institutes are run jointly by SLAC and Stanford.

“For the first time, we’ve seen the atomic-scale details of exactly how these nanoscale materials transform, or switch, from a state that is poorly conducting to one that is highly conducting,” he said. “And what we’ve learned gives us confidence about our ability to tune its structure and properties to be useful in new technologies.”

Lindenberg’s team reported its results last month in Nature Communications.

Copper sulfide is a “superionic” solid material: When heated above a critical temperature it suddenly conducts current, in the form of ions moving through the material, much more readily than at lower temperatures. This transition into a superionic phase has fascinated researchers since the 1830s, when it was first described by the famous British scientist Michael Faraday.

With recent advances in nanoscience, scientists have learned that smaller pieces of superionic material have lower critical temperatures and may also switch states much faster. For instance, a centimeter-sized piece of copper sulfide becomes an excellent conductor when heated above 103 degrees Centigrade, but its fastest recorded switching times occur on a scale of millionths of a second.

In the most recent advance, Lindenberg’s team found that much tinier nanodisks of copper sulfide, just 10 nanometers (10 billionths of a meter) across, switched at lower temperatures – about 70 degrees C. – and can be controlled by light to switch in only 20 trillionths of a second, a million times faster than previously observed.

Superionic materials typically have two constituents – in this case, copper and sulfur –whose structures are intertwined. The new report shows in exquisite detail what happens inside the material when the critical temperature is reached, and indicates a connection between the time it takes for switching to occur and the motion of the ions through the superionic material when it’s at equilibrium.

“This paper presents the first experimental measurements capturing a superionic nanocrystal as it transforms and the associated changes within the transition state itself,” Lindenberg said. “We were surprised how quickly the crystal form and volume changed.”

Now that they know the details of the superionic transformation, Lindenberg says his team has ideas for synthesizing new classes of superionic materials that are stable at room temperature, as well as for exploring the way ions are transported through the material and how the associated transitions from one phase to another take place.

Such an improvement could enable copper sulfide to be used as a key element in new classes of resistive switching devices and as a safe, efficient solid-state replacement for the liquid electrolyte that transports ions between the electrodes of a rechargeable battery.

The researchers conducted their experiments at three synchrotrons: Lawrence Berkeley National Laboratory’s Advanced Light Source, Argonne National Laboratory’s Advanced Photon Source and SLAC’s Stanford Synchrotron Radiation Lightsource. The paper’s first author, Stanford graduate student Tim Miller, received the 2012 Melvin P. Klein Scientific Development Award last fall for his work on this project.

Publication: T. A. Miller, et al., “The mechanism of ultrafast structural switching in superionic copper (I) sulphide nanocrystals,” Nature Communications 4, Article number: 1369; doi:10.1038/ncomms2385

Source: SLAC National Accelerator Laboratory

Image: Greg Stewart/SLAC National Accelerator Laboratory


Synthetic Biology Circuits Perform Logic Functions and Remember the Results

Synthetic Biology Circuits Perform Logic Functions and Remember the Results

February 11, 2013 by Staff

via SciTechDaily


Engineers at MIT have developed genetic circuits in bacterial cells that not only perform logic functions, but also remember the results. Image: Liang Zong and Yan Liang

Researchers at MIT have developed new synthetic biology circuits that combine memory and logic.

MIT engineers have created genetic circuits in bacterial cells that not only perform logic functions, but also remember the results, which are encoded in the cell’s DNA and passed on for dozens of generations.

The circuits, described in the Feb. 10 online edition of Nature Biotechnology, could be used as long-term environmental sensors, efficient controls for biomanufacturing, or to program stem cells to differentiate into other cell types.

“Almost all of the previous work in synthetic biology that we’re aware of has either focused on logic components or on memory modules that just encode memory. We think complex computation will involve combining both logic and memory, and that’s why we built this particular framework to do so,” says Timothy Lu, an MIT assistant professor of electrical engineering and computer science and biological engineering and senior author of the Nature Biotechnology paper.

Lead author of the paper is MIT postdoc Piro Siuti. Undergraduate John Yazbek is also an author.

More than logic

Synthetic biologists use interchangeable genetic parts to design circuits that perform a specific function, such as detecting a chemical in the environment. In that type of circuit, the target chemical would generate a specific response, such as production of green fluorescent protein (GFP).

Circuits can also be designed for any type of Boolean logic function, such as AND gates and OR gates. Using those kinds of gates, circuits can detect multiple inputs. In most of the previously engineered cellular logic circuits, the end product is generated only as long as the original stimuli are present: Once they disappear, the circuit shuts off until another stimulus comes along.

Lu and his colleagues set out to design a circuit that would be irreversibly altered by the original stimulus, creating a permanent memory of the event. To do this, they drew on memory circuits that Lu and colleagues designed in 2009. Those circuits depend on enzymes known as recombinases, which can cut out stretches of DNA, flip them, or insert them. Sequential activation of those enzymes allows the circuits to count events happening inside a cell.

Lu designed the new circuits so that the memory function is built into the logic gate itself. With a typical cellular AND gate, the two necessary inputs activate proteins that together turn on expression of an output gene. However, in the new circuits, the inputs stably alter regions of DNA that control GFP production. These regions, known as promoters, recruit the cellular proteins responsible for transcribing the GFP gene into messenger RNA, which then directs protein assembly.

For example, in one circuit described in the paper, two DNA sequences called terminators are interposed between the promoter and the output gene (GFP, in this case). Each of these terminators inhibits the transcription of the output gene and can be flipped by a different recombinase enzyme, making the terminator inactive.

Each of the circuit’s two inputs turns on production of one of the recombinase enzymes needed to flip a terminator. In the absence of either input, GFP production is blocked. If both are present, both terminators are flipped, resulting in their inactivation and subsequent production of GFP.

Once the DNA terminator sequences are flipped, they can’t return to their original state — the memory of the logic gate activation is permanently stored in the DNA sequence. The sequence also gets passed on for at least 90 generations. Scientists wanting to read the cell’s history can either measure its GFP output, which will stay on continuously, or if the cell has died, they can retrieve the memory by sequencing its DNA.

Using this design strategy, the researchers can create all two-input logic gates and implement sequential logic systems. “It’s really easy to swap things in and out,” says Lu, who is also a member of MIT’s Synthetic Biology Center. “If you start off with a standard parts library, you can use a one-step reaction to assemble any kind of function that you want.”

Long-term memory

Such circuits could also be used to create a type of circuit known as a digital-to-analog converter. This kind of circuit takes digital inputs — for example, the presence or absence of single chemicals — and converts them to an analog output, which can be a range of values, such as continuous levels of gene expression.

For example, if the cell has two circuits, each of which expresses GFP at different levels when they are activated by their specific input, those inputs can produce four different analog output levels. Moreover, by measuring how much GFP is produced, the researchers can figure out which of the inputs were present.

That type of circuit could offer better control over the production of cells that generate biofuels, drugs or other useful compounds. Instead of creating circuits that are always on, or using promoters that need continuous inputs to control their output levels, scientists could transiently program the circuit to produce at a certain level. The cells and their progeny would always remember that level, without needing any more information.

Used as environmental sensors, such circuits could also provide very precise long-term memory. “You could have different digital signals you wanted to sense, and just have one analog output that summarizes everything that was happening inside,” Lu says.

This platform could also allow scientists to more accurately control the fate of stem cells as they develop into other cell types. Lu is now working on engineering cells to follow sequential development steps, depending on what kinds of inputs they receive from the environment.

Michael Jewett, an assistant professor of chemical and biological engineering at Northwestern University, says the new design represents a “huge advancement in DNA-encoded memory storage.”

“I anticipate that the innovations reported here will help to inspire larger synthetic biology efforts that push the limits of engineered biological systems,” says Jewett, who was not involved in the research.

The research was funded by the Office of Naval Research and the Defense Advanced Research Projects Agency.

Publication: Piro Siuti, et al., “Synthetic circuits integrating logic and memory in living cells,” Nature Biotechnology, 2013; DOI: 10.1038/nbt.2510

Source: Anne Trafton, MIT News Office

Image: Liang Zong and Yan Liang

Reprinted with permission of MIT News


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