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WIRED: NASA's Plutonium Problem Could End Deep-Space Exploration - Earth's Reserves Almost Ran Out

WIRED: NASA's Plutonium Problem Could End Deep-Space Exploration - Earth's Reserves Almost Ran Out | Amazing Science | Scoop.it

In 1977, the Voyager 1 spacecraft left Earth on a five-year mission to explore Jupiter and Saturn. Thirty-six years later, the car-size probe is still exploring, still sending its findings home. It has now put more than 19 billion kilometers between itself and the sun. Last week NASA announced that Voyager 1 had become the first man-made object to reach interstellar space.

 

The distance this craft has covered is almost incomprehensible. It’s so far away that it takes more than 17 hours for its signals to reach Earth. Along the way, Voyager 1 gave scientists their first close-up looks at Saturn, took the first images of Jupiter’s rings, discovered many of the moons circling those planets and revealed that Jupiter’s moon Io has active volcanoes. Now the spacecraft is discovering what the edge of the solar system is like, piercing the heliosheath where the last vestiges of the sun’s influence are felt and traversing the heliopause where cosmic currents overcome the solar wind. Voyager 1 is expected to keep working until 2025 when it will finally run out of power.

 

None of this would be possible without the spacecraft’s three batteries filled with plutonium-238. In fact, Most of what humanity knows about the outer planets came back to Earth on plutonium power. Cassini’s ongoing exploration of Saturn, Galileo’s trip to Jupiter, Curiosity’s exploration of the surface of Mars, and the 2015 flyby of Pluto by the New Horizons spacecraft are all fueled by the stuff. The characteristics of this metal’s radioactive decay make it a super-fuel. More importantly, there is no other viable option. Solar power is too weak, chemical batteries don’t last, nuclear fission systems are too heavy. So, we depend on plutonium-238, a fuel largely acquired as by-product of making nuclear weapons.

 

But there’s a problem: We’ve almost run out. “We’ve got enough to last to the end of this decade. That’s it,” said Steve Johnson, a nuclear chemist at Idaho National Laboratory. And it’s not just the U.S. reserves that are in jeopardy. The entire planet’s stores are nearly depleted.


The country’s scientific stockpile has dwindled to around 36 pounds. To put that in perspective, the battery that powers NASA’s Curiosity rover, which is currently studying the surface of Mars, contains roughly 10 pounds of plutonium, and what’s left has already been spoken for and then some. The implications for space exploration are dire: No more plutonium-238 means not exploring perhaps 99 percent of the solar system. In effect, much of NASA’s $1.5 billion-a-year (and shrinking) planetary science program is running out of time. The nuclear crisis is so bad that affected researchers know it simply as “The Problem.”

 

But it doesn’t have to be that way. The required materials, reactors, and infrastructure are all in place to create plutonium-238. In fact, the U.S. government recently approved spending about $10 million a year to reconstitute production capabilities the nation shuttered almost two decades ago. In March, the DOE even produced a tiny amount of fresh plutonium inside a nuclear reactor in Tennessee.


The only natural supplies of plutonium-238 vanished eons before the Earth formed some 4.6 billion years ago. Exploding stars forge the silvery metal, but its half-life, or time required for 50 percent to disappear through decay, is just under 88 years.

 

Fortunately, we figured out how to produce it ourselves — and to harness it to create a remarkably persistent source of energy. Like other radioactive materials, plutonium-238 decays because its atomic structure is unstable. When an atom’s nucleus spontaneously decays, it fires off a helium core at high speed while leaving behind a uranium atom. These helium bullets, called alpha radiation, collide en masse with nearby atoms within a lump of plutonium — a material twice as dense as lead. The energy can cook a puck of plutonium-238 to nearly 1,260 degrees Celsius. To turn that into usable power, you wrap the puck with thermoelectrics that convert heat to electricity. Voila: You’ve got a battery that can power a spacecraft for decades.


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Single-nucleus Hi-C reveals unique chromatin reorganization at oocyte-to-zygote transition

Single-nucleus Hi-C reveals unique chromatin reorganization at oocyte-to-zygote transition | Amazing Science | Scoop.it

Chromatin is reprogrammed after fertilization to produce a totipotent zygote with the potential to generate a new organism1. The maternal genome inherited from the oocyte and the paternal genome provided by sperm coexist as separate haploid nuclei in the zygote. How these two epigenetically distinct genomes are spatially organized is poorly understood. Existing chromosome conformation capture-based methods2, 3, 4, 5 are not applicable to oocytes and zygotes owing to a paucity of material.

 

To study three-dimensional chromatin organization in rare cell types, a team of scientists developed a single-nucleus Hi-C (high-resolution chromosome conformation capture) protocol that provides greater than tenfold more contacts per cell than the previous method2. They were able to show that chromatin architecture is uniquely reorganized during the oocyte-to-zygote transition in mice and is distinct in paternal and maternal nuclei within single-cell zygotes. Features of genomic organization including compartments, topologically associating domains (TADs) and loops are present in individual oocytes when averaged over the genome, but the presence of each feature at a locus varies between cells. At the sub-megabase level, they observed stochastic clusters of contacts that can occur across TAD boundaries but average into TADs. Notably, they found that TADs and loops, but not compartments, are present in zygotic maternal chromatin, suggesting that these are generated by different mechanisms.

 

Taken together, these results demonstrate that the global chromatin organization of zygote nuclei is fundamentally different from that of other interphase cells. An understanding of this zygotic chromatin ‘ground state’ could potentially provide insights into reprogramming cells to a state of totipotency.

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Our Universe Has A Lithium Problem

Our Universe Has A Lithium Problem | Amazing Science | Scoop.it
The Big Bang Theory predicts three times as much lithium as observed. Where are the scientists hiding our lithium?

 

The missing lithium problem is centered around the earliest stages of the Universe: from about 10 seconds to 20 minutes after the Big Bang. The Universe was super hot and it was expanding rapidly. This was the beginning of what’s called the Photon Epoch. At that time, atomic nuclei formed through nucleosynthesis. But the extreme heat that dominated the Universe prevented the nuclei from combining with electrons to form atoms. The Universe was a plasma of nuclei, electrons, and photons.

 

Only the lightest nuclei were formed during this time, including most of the helium in the Universe, and small amounts of other light nuclides, like deuterium and our friend lithium. For the most part, heavier elements weren’t formed until stars appeared, and took on the role of nucleosynthesis.

 

The problem is that our understanding of the Big Bang tells us that there should be three times as much lithium as there is. The BBT gets it right when it comes to other primordial nuclei. Our observations of primordial helium and deuterium match the BBT’s predictions. So far, scientists haven’t been able to resolve this inconsistency. But a new paper from researchers in China may have solved the puzzle.

 

One assumption in Big Bang nucleosynthesis is that all of the nuclei are in thermodynamic equilibrium, and that their velocities conform to what’s called the classical Maxwell-Boltzmann distribution. But the Maxwell-Boltzmann describes what happens in what is called an ideal gas. Real gases can behave differently, and this is what the researchers propose: that nuclei in the plasma of the early photon period of the Universe behaved slightly differently than thought.

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The Pink Lake Retba is Colored by Halophilic Cyanobacteria

The Pink Lake Retba is Colored by Halophilic Cyanobacteria | Amazing Science | Scoop.it

Lake Retba or Lac Rose lies north of the Cap Vert peninsula of Senegal, north east of Dakar. Depending on the time of day, the lake changes colour from a light purple to a deep scarlet pink. The unusual colouring of the water is caused by harmless halophilic bacteria that thrive in the lake’s high-salinity environment. The color is particularly visible during the dry season.

 

"The strawberry colour is produced by salt-loving organism Dunaliella salina. They produce a red pigment that absorbs and uses the energy of sunlight to create more energy, turning the water pink," said Michael Danson, an expert in bacteria from Britain's Bath University.

 

Covering an area of about 3 sq km, the lake is located about 35km north-east of Senegal’s capital Dakar. Since the 1970s, local residents have been mining Lake Retba for its salt, which they use mainly to preserve fish. Waist-deep in water, the men scrape the bottom of the lake to harvest this universally useful mineral which they collect in baskets in their wooden canoes. The salt is then taken back to shore where it is sectioned into small mounds. Dotted along the lake’s shore, these pristine white hills of salt create an arresting contrast against the pink of the lake. In order to protect their skin from the extreme salinity of the water, the workers rub their skin with shea butter, produced from shea nuts obtained from the Shea nut tree.

 

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Herpes May Have Been Transmitted from Chimps to Humans 30,000 Years Ago

Herpes May Have Been Transmitted from Chimps to Humans 30,000 Years Ago | Amazing Science | Scoop.it
Researchers say the lineages of HSV-1 and HSV-2 show herpes viruses mixed genomes and moved from chimps to humans. How it was transmitted is a bit of a mystery.

 

There are two main types of herpes virus around today.

The herpes simplex virus 1 (HSV-1) is transmitted mostly by mouth and is found most often in cold sores. This ailment affects about two-thirds of the world’s population.

 

The herpes simplex virus 2 (HSV-2) is the main source for genital herpes. It affects about 11 percent of people around the globe. The HSV-2 strain has been used to help verify the “Out of Africa” theory that humans began migrating from that continent more than 50,000 years ago.

 

In general, HSV-1 and HSV-2 are considered cousins and have been thought to have evolved separately. However, the researchers of the study took a closer look at the evolution of the herpes virus, building on the work done in a 2014 study. The team, led by Sebastien Calvignac-Spencer, PhD, of the Robert Koch Institut in Germany, examined the whole genome sequencing data of 18 HSV-2 isolates.

 

The researchers say they determined the two main lineages of HSV-2 began diversifying about 30,000 years ago. One strain was restricted to Sub-Saharan Africa, while the other spread globally. Calvignac-Spencer told Healthline in an email that the HSV-2 strain eventually mixed its genome with the HSV-1 strain.

He said this mixture did not occur in all HSV-2, but the HSV-2 lineage that spread around the world contains the presence of HSV-1 recombinant fragments.

 

“We don't know whether there is a causal relationships and these HSV-1 fragments provided a selective advantage to this lineage, but that is clearly one intriguing possibility,” Calvignac-Spencer said.

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Ovulation in the lab: Mini reproductive organs in a dish mimic 28-day menstrual cycle

Ovulation in the lab: Mini reproductive organs in a dish mimic 28-day menstrual cycle | Amazing Science | Scoop.it

It’s ovulation in the lab. A simulated female reproductive system behaves almost like the real thing over 28 days. “Menstruation in a dish is one of my goals,” says Julie Kim of Northwestern University in Chicago. Kim works with organoids – small 3D clumps of tissue that behave more naturally than traditional, flat cell cultures. Linking different organoids together enables researchers to study complex organ systems in miniature, an approach that could lead to new insights and less animal testing.

 

Now Kim’s team has hooked up tissue from the ovaries, uterus, cervix and fallopian tubes, as well as the liver, which makes compounds that help to transport hormones. The tissues responded to hormones made by the mini ovary: oestrogen in the first two weeks, then progesterone for the next two weeks. In the first half of the cycle, eggs grew and burst out of the ovary – mimicking ovulation. Tiny hairs in the fallopian tube began to beat faster, as if to waft the egg along, while cells in the uterus proliferated.

 

But the uterine cells didn’t die and break away during the progesterone phase, which normally triggers menstruation – probably because the uterine organoid had no blood vessels. Kim is now introducing these, but she hasn’t yet managed to get them to break down, which should prompt the uterine cells to die off. If Kim’s team manages to complete the miniature menstrual cycle, it may lead to treatments for painful periods, fibroids and infertility.

 

“Having this functional axis between the ovaries and the other organs is what makes this so interesting,” saysAnthony Atala at the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina. “In our body it’s not just the isolated organ that’s doing the work; you have these interactions with other organs.”

 

Journal reference: Nature Communications, DOI: 10.1038/ncomms14584

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Deadly heat stress could threaten hundreds of millions in megacities even if climate targets reached

Deadly heat stress could threaten hundreds of millions in megacities even if climate targets reached | Amazing Science | Scoop.it

A global temperature rise of 1.5℃ above pre-industrial levels could have devastating consequences for city dwellers.

 

Deadly heat stress is projected to affect hundreds of millions more people each year under relatively little additional climate warming. The Paris Agreement commits the international community to limit global warming to no more than 2℃ above pre-industrial (late 19th century) air temperatures, with an aspirational target of 1.5℃. In our latest research, which looked at the impact of global temperature rises on megacities, we foundthat even if 1.5℃ is achieved, large increases in the frequency of deadly heat are expected. By 2050 about 350m more people living in megacities could be exposed to deadly heat each year.

 

Humans become “heat stressed” when the body absorbs more heat than is tolerable. If core body temperature rises just a few degrees above 37℃, deadly heatstroke can result. By using its cooling system – sweating – the human body can maintain a safe temperature even if air temperatures rise above 37℃. This mechanism works better in a drier atmosphere (which is why steam rooms feel hotter than saunas – even at the same air temperature). The heat index is a measure that combines this humidity effect with air temperature to provide a “feels like” temperature. A heat index in excess of about 40.6℃ is considered dangerous to human health.

 

As global air temperatures rise, observations and experiments with climate models suggest that atmospheric moisture content also climbs. This means that the heat index (and how hot it feels) rises faster than air temperature. Also, because the amount of moisture the atmosphere can hold increases more rapidly at higher temperatures, the heat index rises faster too, a non-linear response.

 

This non-linear response carries over to the definition of “global heat stress burden” used in our research, which we define as the average number of days per year over land areas with a daily heat index above 40.6℃. Using a large number of climate model simulations, we found that this quantity increases faster and faster as global average air temperatures rise. This sharp rise in global heat stress burden has important consequences.

First, any increase in global heat stress from climate warming to date will be smaller than that caused by the same additional warming in the future. We have already seen a 0.8℃ rise in global temperature, another 0.8℃ of warming could be expected to lead to a greater increase in heat stress than caused by the first 0.8℃.

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Planet-sized 'waves' spotted in the Sun's atmosphere

Planet-sized 'waves' spotted in the Sun's atmosphere | Amazing Science | Scoop.it
Long-sought features may help researchers to improve models of solar activity and predict space weather.

 

Huge ripples in Earth’s atmosphere called Rossby waves help to steer the planet's jet streams and weather patterns. Now, a study in Nature Astronomy offers the best evidence yet  that similar large-scale features also exist on the Sun1.

 

Rossby waves were  discovered in Earth’s atmosphere in the late 1930s. Driven by a planet's rotation, they’ve been seen in the atmospheres of other planets, as well as in Earth’s oceans. In theory, these waves can form in any rotating fluid, says Scott McIntosh, a solar physicist at the National Center for Atmospheric Research in Boulder, Colorado and lead study author.

 

Researchers have long sought evidence of Rossby waves on the Sun, he says. And an enhanced understanding of these features and their movements could help scientists to better predict the formation of sunspots and the eruption of solar flares.

 

In the past, astronomers have been hampered in their search for the waves by their limited view of the Sun, because only one side can be viewed from Earth. But three solar probes — part of NASA's Solar Dynamics Observatory and its Solar Terrestrial Relations Observatory (STEREO) mission — were positioned for several years to give scientists a 360° view of the Sun’s atmosphere, or corona. (Astronomers lost communication with one STEREO probe after it slid behind the Sun in mid-2014.)

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After the ISS: Big Plans for Commercial Space Habitats

After the ISS: Big Plans for Commercial Space Habitats | Amazing Science | Scoop.it

Have you ever dreamt of living in outer space? Since the development of spaceflight, the off-Earth lifestyle has been limited to the select few aboard the International Space Station. For nearly 19 years, the station has played host to rotating teams of highly-trained international astronauts.

 

The ISS, however, may be nearing the end of its tenure in low-Earth orbit.1 While the U.S., Russia, Europe, Canada and Japan have all extended their involvement in ISS operations until 2024,2 the venerable space station may be facing decommission shortly thereafter. This doesn’t mean that we’re abandoning the idea of living in space—in fact, because of they way they are exiting, it signals precisely the opposite.

 

Soon, orbiting living spaces will no longer be the exclusive domain of agency-affiliated astronauts. Like so much in space, habitats are going commercial. By the 2020’s, NASA’s intention is to transition low-Earth orbit to the private sector—in terms of both supply and demand.3


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Scientists finally evade Heisenberg's uncertainty principle

Scientists finally evade Heisenberg's uncertainty principle | Amazing Science | Scoop.it

ICFO Researchers report the discovery of a new technique that could drastically improve the sensitivity of instruments such as magnetic resonance imagers (MRIs) and atomic clocks. The study, published in Nature, reports a technique to bypass the Heisenberg uncertainty principle. This technique hides quantum uncertainty in atomic features not seen by the instrument, allowing the scientists to make very high precision measurements.

 

State-of-the-art sensors, such as MRIs and atomic clocks, are capable of making measurements with exquisite precision. MRI is used to image tissues deep within the human body and tells us whether we might suffer from an illness, while atomic clocks are extremely precise timekeepers used for GPS, internet synchronization, and long baseline interferometry in radio-astronomy. One might think these two instruments have nothing in common, but they do: both technologies are based on precise measurement the spin of the atom, the gyroscope-like motion of the electrons and the nucleus. In MRI, for example, the pointing angle of the spin gives information about where in the body the atom is located, while the amount of spin (the amplitude) is used to distinguish different kinds of tissue. Combining these two pieces of information, the MRI can make a 3D map of the tissues in the body.

 

The sensitivity of this kind of measurement was long thought to be limited by Heisenberg's uncertainty principle, which states that accurately measuring one property of an atom puts a limit to the precision of measurement you can obtain on another property. For example, if we measure an electron's position with high precision, Heisenberg's principle limits the accuracy in the measurement of its momentum. Since most atomic instruments measure two properties (spin amplitude and angle), the principle seems to say that the readings will always contain some quantum uncertainty.

 

This long-standing expectation has now been disproven, however, by ICFO researchers Dr. Giorgio Colangelo, Ferran Martin Ciurana, Lorena C. Bianchet and Dr. Robert J. Sewell, led by ICREA Prof. at ICFO Morgan W. Mitchell. In their article "Simultaneous tracking of spin angle and amplitude beyond classical limits", published this week in Nature, they describe how a properly designed instrument can almost completely avoid quantum uncertainty.

 

The trick is to realize that the spin has not one but two pointing angles, one for the north-east-south-west direction, and the other for the elevation above the horizon. The ICFO team showed how to put nearly all of the uncertainty into the angle that is not measured by the instrument. In this way they still obeyed Heisenberg's requirement for uncertainty, but hid the uncertainty where it can do no harm. As a result, they were able to obtain an angle-amplitude measurement of unprecedented precision, unbothered by quantum uncertainty.

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Secrets hidden by the Fibonacci Number and Phi (Φ)

Secrets hidden by the Fibonacci Number and Phi (Φ) | Amazing Science | Scoop.it

The Fibonacci numbers are the sequence of numbers defined by the linear recurrence equation.

 

The plot above shows the first 511 terms of the Fibonacci sequence represented in binary, revealing an interesting pattern of hollow and filled triangles (Pegg 2003). A fractal-like series of white triangles appears on the bottom edge, due in part to the fact that the binary representation of ends in zeros. Many other similar properties exist.

 

The Fibonacci numbers give the number of pairs of rabbits months after a single pair begins breeding (and newly born bunnies are assumed to begin breeding when they are two months old), as first described by Leonardo of Pisa (also known as Fibonacci) in his book Liber Abaci. Kepler also described the Fibonacci numbers (Kepler 1966; Wells 1986, pp. 61-62 and 65). Before Fibonacci wrote his work, the Fibonacci numbers had already been discussed by Indian scholars such as Gopāla (before 1135) and Hemachandra (c. 1150) who had long been interested in rhythmic patterns that are formed from one-beat and two-beat notes or syllables. The number of such rhythms having beats altogether is , and hence these scholars both mentioned the numbers 1, 2, 3, 5, 8, 13, 21, ... explicitly (Knuth 1997, p. 80).

 

The numbers of Fibonacci numbers less than 10, , , ... are 6, 11, 16, 20, 25, 30, 35, 39, 44, ... (OEIS A072353). For , 2, ..., the numbers of decimal digits in are 2, 21, 209, 2090, 20899, 208988, 2089877, 20898764, ... (OEIS A068070). As can be seen, the initial strings of digits settle down to produce the number 208987640249978733769..., which corresponds to the decimal digits of (OEIS A097348), where is the golden ratio. This follows from the fact that for any power function , the number of decimal digits for is given by .

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NASA's Swift Mission Maps a Star's 'Death Spiral' into a Black Hole

NASA's Swift Mission Maps a Star's 'Death Spiral' into a Black Hole | Amazing Science | Scoop.it
Some 290 million years ago, a star much like the sun wandered too close to the central black hole of its galaxy. Intense tides tore the star apart, which produced an eruption of optical, ultraviolet and X-ray light that first reached Earth in 2014.
 
Now, a team of scientists using observations from NASA's Swift satellite have mapped out how and where these different wavelengths were produced in the event, named ASASSN-14li, as the shattered star's debris circled the black hole.
 
"We discovered brightness changes in X-rays that occurred about a month after similar changes were observed in visible and UV light," said Dheeraj Pasham, an astrophysicist at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, and the lead researcher of the study. "We think this means the optical and UV emission arose far from the black hole, where elliptical streams of orbiting matter crashed into each other."
 
Astronomers think ASASSN-14li was produced when a sun-like star wandered too close to a 3-million-solar-mass black hole similar to the one at the center of our own galaxy. For comparison, the event horizon of a black hole like this is about 13 times bigger than the sun, and the accretion disk formed by the disrupted star could extend to more than twice Earth's distance from the sun.
 
When a star passes too close to a black hole with 10,000 or more times the sun's mass, tidal forces outstrip the star's own gravity, converting the star into a stream of debris. Astronomers call this a tidal disruption event. Matter falling toward a black hole collects into a spinning accretion disk, where it becomes compressed and heated before eventually spilling over the black hole's event horizon, the point beyond which nothing can escape and astronomers cannot observe. Tidal disruption flares carry important information about how this debris initially settles into an accretion disk.
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Funnel web spider venom can protect cells from being destroyed by a stroke

Funnel web spider venom can protect cells from being destroyed by a stroke | Amazing Science | Scoop.it

Doctors have stumbled on an unlikely source for a drug to ward off brain damage caused by strokes: the venom of one of the deadliest spiders in the world.

 

A bite from an Australian funnel web spider can kill a human in 15 minutes, but a harmless ingredient found in the venom can protect brain cells from being destroyed by a stroke, even when given hours after the event, scientists say. If the compound fares well in human trials, it could become the first drug that doctors have to protect against the devastating loss of neurons that strokes can cause.

 

Researchers discovered the protective molecule by chance as they sequenced the DNA of toxins in the venom of the Darling Downs funnel web spider (Hadronyche infensa) that lives in Queensland and New South Wales. Venom from three spiders was gathered for the study after scientists trapped and “milked exhaustively” three spiders on Orchid beach, about 400km north of Brisbane.

 

The molecule, called Hi1a, stood out because it looked like two copies of another brain cell-protecting chemical stitched together. It was so intriguing that scientists decided to synthesize the compound and test its powers. “It proved to be even more potent,” said Glenn King at the University of Queensland’s centre for pain research.

 

Strokes occur when blood flow to the brain is interrupted and the brain is starved of oxygen. About 85% of strokes are caused by blockages in blood vessels in the brain, with the rest due to bleeds when vessels rupture. Approximately six million people a year die from stroke, making it the second largest cause of death worldwide after heart attacks.

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Neil Sloane: The Connoisseur of Number Sequences

Neil Sloane: The Connoisseur of Number Sequences | Amazing Science | Scoop.it
For more than 50 years, the mathematician Neil Sloane has curated the authoritative collection of interesting and important integer sequences.

 

Neil Sloane is considered by some to be one of the most influential mathematicians of our time. That’s not because of any particular theorem the 75-year-old Welsh native has proved, though over the course of a more than 40-year research career at Bell Labs (later AT&T Labs) he won numerous awards for papers in the fields of combinatorics, coding theory, optics and statistics. Rather, it’s because of the creation for which he’s most famous: the Online Encyclopedia of Integer Sequences (OEIS), often simply called “Sloane” by its users.

 

This giant repository, which celebrated its 50th anniversary last year, contains more than a quarter of a million different sequences of numbers that arise in different mathematical contexts, such as the prime numbers (2, 3, 5, 7, 11 … ) or the Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, 13 … ). What’s the greatest number of cake slices that can be made with n cuts?

 

Look up sequence A000125 in the OEIS. How many chess positions can be created in n moves? That’s sequence A048987. The number of ways to arrange n circles in a plane, with only two crossing at any given point, is A250001. That sequence just joined the collection a few months ago. So far, only its first four terms are known; if you can figure out the fifth, Sloane will want to hear from you.

 

A mathematician whose research generates a sequence of numbers can turn to the OEIS to discover other contexts in which the sequence arises and any papers that discuss it. The repository has spawned countless mathematical discoveries and has been cited more than 4,000 times.

 

“Many mathematical articles explicitly mention how they were inspired by OEIS, but for each one that does, there are at least ten who do not mention it, not necessarily out of malice, but because they take it for granted,” wrote Doron Zeilberger, a mathematician at Rutgers University.

 

A recent scientific paper about the OEIS database can be found here (by J.M. Borwein).

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When Science, Math and Art Meets: ImageQuilts

When Science, Math and Art Meets: ImageQuilts | Amazing Science | Scoop.it

Thomas Baruchel’s website shows images derived from complex analysis. John D. Cook used the ImageQuilts software by Edward Tufte and Adam Schwartz to create a large variety of scientific and artistic images.

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Watch stars orbit Milky Ways supermassive black hole

Watch stars orbit Milky Ways supermassive black hole | Amazing Science | Scoop.it

There is a supermassive black hole with a mass of 4 million suns in the center of the Milky Way galaxy and it is influencing surrounding stars with its gravity. People have been thinking about black holes since 1783. That year, English clergyman John Michell proposed the idea of “dark stars” so massive and gravitationally powerful they could imprison their own light. Michell wasn’t making wild assumptions but taking the idea of gravity to a logical conclusion. Of course, he had no way to prove his assertion. But we do now. Astronomers  routinely find bot stellar mass black holes — remnants of the collapse of gas-guzzling supergiant stars — and the supermassive variety in the cores of galaxies that result from multiple black hole mergers over grand intervals of time.

 

Some of the galactic variety contain hundreds of thousands to billions of solar masses, all of it so to speak “flushed down the toilet” and unavailable to fashion new planets and stars. Famed physicist Stephen Hawking has shown that black holes evaporate over time, returning their energy to the knowable universe from whence they came, though no evidence of the process has yet been found.

 

A recent time-lapse movie in infrared light shows how stars in the central light-year of the Milky Way have moved over a period of 14 years. The image center represents the location of Sgr A*, which is the precise site of an unseen supermassive black hole. Based on those speeds they can calculate the mass of what’s doing the pulling.

 

In the case of the galaxy M87 located 53.5 million light years away in the Virgo Cluster, those speeds tell us that something with a mass of 3.6 billion suns is concentrated in a space smaller than our Solar System.

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Phenanthridine PJ34 Causes Fast Cell Death During Cancer Cell Mitosis and Spares Normal Cells

Phenanthridine PJ34 Causes Fast Cell Death During Cancer Cell Mitosis and Spares Normal Cells | Amazing Science | Scoop.it

Proteins that can be specifically modified during mitosis, the division process, to unleash an inherent death mechanism that self-eradicates duplicating cancer cells have been identified by researchers at Tel Aviv University. Many cancer patients struggle with the adverse effects of chemotherapy, still the most prescribed cancer treatment. For patients with pancreatic cancer and other aggressive cancers, the forecast is more grim: there is no known effective therapy.

 

Prof. Malka Cohen-Armon, study leader, said: “The discovery of an exclusive mechanism that kills cancer cells without impairing healthy cells, and the fact that this mechanism works on a variety of rapidly proliferating human cancer cells, is very exciting. According to the mechanism we discovered, the faster cancer cells proliferate, the faster and more efficiently they will be eradicated. The mechanism unleashed during mitosis may be suitable for treating aggressive cancers that are unaffected by traditional chemotherapy. Our experiments in cell cultures tested a variety of incurable human cancer types; breast, lung, ovary, colon, pancreas, blood, brain. This discovery impacts existing cancer research by identifying a new specific target mechanism that exclusively and rapidly eradicates cancer cells without damaging normally proliferating human cells.”

 

The newly-discovered mechanism involves the modification of specific proteins that affect the construction and stability of the spindle, the microtubular structure that prepares duplicated chromosomes for segregation into “daughter” cells during cell division. The researchers found that certain compounds called Phenanthridine derivatives were able to impair the activity of these proteins, which can distort the spindle structure and prevent the segregation of chromosomes. Once the proteins were modified, the cell was prevented from splitting, and this induced the cell’s rapid self-destruction.

 

“The mechanism we identified during the mitosis of cancer cells is specifically targeted by the Phenanthridine derivatives we tested,” Prof. Cohen-Armon said. “However, a variety of additional drugs that also modify these specific proteins may now be developed for cancer cell self-destruction during cell division. The faster the cancer cells proliferate, the more quickly they are expected to die.” The phenanthrenes PJ34, Phen and Tiq-A, the researchers found, modify kinesins (HSET/kifC1 and kif18A) and NuMA (nuclear mitotic apparatus protein) in a variety of human cancer cells. The most efficient cell killing activity was seen with phenanthridine PJ34, which caused significantly smaller aberrant spindles.

 

Reference: Visochek, L., Castiel, A., Mittelman, L., Elkin, M., Atias, D., Golan, T., Izraeli, S., Peretz, T., & Cohen-Armon, M. (2017) Exclusive destruction of mitotic spindles in human cancer cells Oncotarget, 8(13), 20813-20824

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The Fascinating Art of Whistled Speech: Over 70 Still Exist

The Fascinating Art of Whistled Speech: Over 70 Still Exist | Amazing Science | Scoop.it
From Amazonia to Siberia, some human populations the world over communicate by whistling. More complex than it sounds, whistled speech intrigues linguists and neuroscientists alike. Linguist and bio-acoustician Julien Meyer tells us about this astonishing method of communication.

 

Imagine you're working in your vegetable garden or looking after your animals—livelihood activities that humans have carried out for centuries in the countryside and in the mountains. Now suppose that for some reason, you need to talk to a friend on the hill opposite. Forget about your mobile: networks don't always work properly in the mountains. You could always go over to have a word, but that would be too much trouble: a waste of energy, let alone time. You could also shout, but that would only serve to attract attention: the greater the distance travelled by the human voice, the more incomprehensible it becomes. Not to mention the fact that you would soon strain your vocal chords. So why not try whistling?

 

A good whistle would easily reach its target. It carries much further than a shout, up to several kilometers in the mountains, in the right terrain and weather conditions. A whistle is concentrated sound energy in a narrow band of much higher frequencies than nature's usual background noise. This is only a short step from holding a full conversation at a distance—and one that was taken thousands of years ago by a number of populations around the world. 
 
Whistled speech is a fascinating phenomenon. Just like shouting, whispering, and singing, it is a form derived from the language spoken locally. It survives exclusively in environments where human communication is extremely difficult, such as dense tropical forest and steep mountain valleys. Today, linguists and neuroscientists are intrigued by whistled speech, which can convey words and complex sentences while using only a very limited range of vocal sounds. 

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Supermassive black holes give birth to stars, astronomers discover

Supermassive black holes give birth to stars, astronomers discover | Amazing Science | Scoop.it
A team of astrophysicists has discovered that supermassive black holes at the centre of galaxies aren't just destroyers of stars, but also their creators.

 

Stellar black holes form from the collapse of a large star. They can have a mass of 20 times that of of our sun or higher, and they consume anything that gets too close, including a star. There's another category of these stellar gourmands: supermassive black holes. These have masses more than one billion times that of the sun and lurk at the centre of most galaxies, including our own. While it was suspected that these supermassive black holes could actually be giving rise to new stars while simultaneously destroying unfortunate interlopers, there wasn't enough direct evidence to support that theory. Until now.

 

Recently, a team of European astronomers was observing the collision of two galaxies some 600 million light-years away — each with a supermassive black hole at its centre —  using the Very Large Telescope (VLT) in Chile. There, they found evidence of new star birth from material being ejected from the black hole, called an outflow. While it might seem a contradiction that nothing can escape a black hole, but an outflow of gas is responsible for creating new stars, it's all about the location: nothing can escape a black hole once it gets so close that all matter is sucked in and can't escape.

 

However, the gases that swirl around the centre of the black hole — think of water going down a drain — exist in something called an accretion disc. It's from there that gases are heated to incredible temperatures and then are rapidly ejected into space. Astronomers believe that some of the material might be flung out of the galaxy altogether.

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Paralyzed man moves arm using power of thought in world first

Paralyzed man moves arm using power of thought in world first | Amazing Science | Scoop.it

A man who was paralysed from below the neck after crashing his bike into a truck can once again drink a cup of coffee and eat mashed potato with a fork, after a world-first procedure to allow him to control his hand with the power of thought.

 

Bill Kochevar, 53, has had electrical implants in the motor cortex of his brain and sensors inserted in his forearm, which allow the muscles of his arm and hand to be stimulated in response to signals from his brain, decoded by computer. After eight years, he is able to drink and feed himself without assistance.

 

“I think about what I want to do and the system does it for me,” Kochevar explained. “It’s not a lot of thinking about it. When I want to do something, my brain does what it does.” The experimental technology, pioneered by the Case Western Reserve University in Cleveland, Ohio, is the first in the world to restore brain-controlled reaching and grasping in a person with complete paralysis.

 

For now, the process is relatively slow, but the scientists behind the breakthrough say this is proof of concept and that they hope to streamline the technology until it becomes a routine treatment for people with paralysis. In the future, they say, it will also be wireless and the electrical arrays and sensors will all be implanted under the skin and invisible.

 

“Our research is at an early stage, but we believe that this neuroprosthesis could offer individuals with paralysis the possibility of regaining arm and hand functions to perform day-to-day activities, offering them greater independence,” said Dr Bolu Ajiboye, lead author of a paper detailing the research in the Lancet medical journal.

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Periodic Table of Mathematical Objects: The L-functions and Modular Forms Database

Periodic Table of Mathematical Objects: The L-functions and Modular Forms Database | Amazing Science | Scoop.it

A team of more than 80 mathematicians from 12 countries has begun charting the terrain of rich, new mathematical worlds, and sharing their discoveries on the Web. The mathematical universe is filled with both familiar and exotic items, many of which are being made available for the first time.

 

The "L-functions and Modular Forms Database," abbreviated LMFDB, is an intricate catalog of mathematical objects and the connections between them. Making those relationships visible has been made possible largely by the coordinated efforts of a group of researchers developing new algorithms and performing calculations on an extensive network of computers. The project provides a new tool for several branches of mathematics, physics, and computer science.

 

A "periodic table" of mathematical objects

Project member John Voight, from Dartmouth College, observed that "our project is akin to the first periodic table of the elements. We have found enough of the building blocks that we can see the overall structure and begin to glimpse the underlying relationships." Similar to the elements in the periodic table, the fundamental objects in mathematics fall into categories. Those categories have names like L-function, elliptic curve, and modular form. The L-functions play a special role, acting like 'DNA' which characterizes the other objects. More than 20 million objects have been catalogued, each with its L-function that serves as a link between related items. Just as the value of genome sequencing is greatly increased when many members of a population have been sequenced, the comprehensive material in the LMFDB will be an indispensible tool for new discoveries.

 

The LMFDB provides a sophisticated web interface that allows both experts and amateurs to easily navigate its contents. Each object has a "home page" and links to related objects, or "friends." Holly Swisher, a project member from Oregon State University, commented that the friends links are one of the most valuable aspects of the project: "The LMFDB is really the only place where these interconnections are given in such clear, explicit, and navigable terms. Before our project it was difficult to find more than a handful of examples, and now we have millions."

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Double filters allow for highly enhanced tetrachromatic vision in humans

Double filters allow for highly enhanced tetrachromatic vision in humans | Amazing Science | Scoop.it

A team of researchers at the University of Wisconsin has developed a pair of glasses that allows the wearer to have tetrachromatic vision. In their paper uploaded to the arXiv preprint sever, the group describes the inspiration for their glasses and explain how they work.

 

Humans have three types of cone cells in the back of the eye to differentiate color. Some react to blue, some to green and some to red. The cones do their work by responding to the difference in wavelength of the incoming light. Such vision is known as trichromatic. In this new effort, the researchers have found a way of fooling the brain into seeing as if there were a fourth type of cone, by wearing glasses with two types of filters. The result is tetrachromatic vision.

 

To create the glasses, the researchers fashioned two types of filters, one for each eye. The filters remove some parts of the blue light spectrum. But the filters each remove a different part. When the filters are fitted into a frame and worn like regular glasses, the wearer is able to see colors that are normally hidden—metamers. In a sense, it is rather the opposite of what occurs with people who are color blind. They might see blue and red as the same, even though there is more light information there. Adding spectrum identification to color blind eyes allows for seeing more of what is already there. With the new combined filter system, a person is able to look at what appears to be an object that is all the same color, such as purple, and see more colors in it—those normally hidden metamers.

 

The team notes that it should be possible to extend the idea used to create their glasses to the other two colors that cone cells process, red and green, to create glasses that offer the ability to see six basic types of colors instead of the normal three. They plan to start with green. Such glasses, the team notes, might be used to spot counterfeit money, or to see a person in the jungle wearing camouflage.

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When Art, Science and Strange Attractors Meet

In the mathematical field of dynamical systems, an attractor is a set of numerical values toward which a system tends to evolve, for a wide variety of starting conditions of the system.[1] System values that get close enough to the attractor values remain close even if slightly disturbed.

 

An attractor is called strange if it has a fractal structure.[1] This is often the case when the dynamics on it are chaotic, but strange nonchaotic attractors also exist. If a strange attractor is chaotic, exhibiting sensitive dependence on initial conditions, then any two arbitrarily close alternative initial points on the attractor, after any of various numbers of iterations, will lead to points that are arbitrarily far apart (subject to the confines of the attractor), and after any of various other numbers of iterations will lead to points that are arbitrarily close together. Thus a dynamic system with a chaotic attractor is locally unstable yet globally stable: once some sequences have entered the attractor, nearby points diverge from one another but never depart from the attractor.[5]

 

The term strange attractor was coined by David Ruelle and Floris Takens to describe the attractor resulting from a series of bifurcations of a system describing fluid flow.[6] Strange attractors are often differentiable in a few directions, but some are like a Cantor dust, and therefore not differentiable. Strange attractors may also be found in presence of noise, where they may be shown to support invariant random probability measures of Sinai–Ruelle–Bowen type.[7]

 

Examples of strange attractors include the double-scroll attractor, Hénon attractor, Rössler attractor, Tamari attractor, and the Lorenz attractor.

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Mars volcano Arsia Mons was very active when Earth's dinosaurs went extinct

Mars volcano Arsia Mons was very active when Earth's dinosaurs went extinct | Amazing Science | Scoop.it

New NASA research reveals that the giant Martian shield volcano Arsia Mons produced one new lava flow at its summit every 1 to 3 million years during the final peak of activity. The last volcanic activity there ceased about 50 million years ago—around the time of Earth's Cretaceous-Paleogene extinction, when large numbers of our planet's plant and animal species (including dinosaurs) went extinct.

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Rosetta tracks massive landslide on Comet 67P

Rosetta tracks massive landslide on Comet 67P | Amazing Science | Scoop.it

A landslide on comet 67P/Churyumov–Gerasimenko triggered a plume of dust to be ejected, revealing pristine ice hidden beneath the surface.

 

In July 2015, the Rosetta spacecraft observed an outburst from the comet. Images from on board cameras had shown numerous surface changes taking place over the two years of observation. However, one in particular was of interest to researchers.

 

Outbursts are often seen on comets, but what causes them is not known. To understand what happens on the surface at the point of these outbursts, an international team of researchers studied an event on Comet 67P.

 

In two studies – one published in Nature Astronomy, the other in Science – researchers showed that landslides had taken place on the comet, with whole cliffs collapsing, drastically altering the surface landscape.

 

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Cerealia Facula: Researchers Determine Age of Ceres’ Brightest Spot

Cerealia Facula: Researchers Determine Age of Ceres’ Brightest Spot | Amazing Science | Scoop.it
Cerealia Facula, a dome-like feature located in the center of Ceres’ Occator crater, is only 4 million years old -- approximately 30 million years younger than the crater itself, according to research led by Dr. Andreas Nathues of the Max Planck Institute for Solar System Research.

 

Occator crater is one of the largest craters on the dwarf planet Ceres. With a diameter of 57 miles (92 km), it is larger than Tycho crater on the Moon. Its steep walls stand tall at over 1.4 miles (2 km), higher than the North face of the Eiger in the Bernese Alps.

 

“Occator crater is located in the northern hemisphere of Ceres. In its center a pit with a diameter of about 6.8 miles (11 km) can be found. On some parts of its edges, jagged mountains and steep slopes rise up to 2,460 feet (750 m) high,” Dr. Nathues and co-authors said. “Within the pit a bright dome formed. It is 1,312 feet (400 m) high, has a diameter of 1.9 miles (3 km), and displays prominent fractures.”

 

“This dome, called Cerealia Facula, contains the brightest material on Ceres.”

 

The researchers analyzed data from two instruments on board NASA’s Dawn spacecraft: the framing camera, and the visible and infrared spectrometer (VIR). VIR data show that Cerealia Facula is very rich in carbonate salts.

 

Since later impacts in this area did not expose any other material from the depth, this feature possibly consists entirely of bright material. The secondary, smaller bright areas of Occator, called Vinalia Faculae, are paler, form a thinner layer and — as VIR and camera data show — turn out to be a mixture of carbonates and dark surrounding material.

 

New evidence also suggests that Cerealia Facula likely rose in a process that took place over a long period of time, rather than forming in a single event. Dr. Nathues and his colleagues believe the initial trigger was the impact that dug out Occator crater. This impact happened some 34 million years ago and caused briny liquid to rise closer to the surface.

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