Nyeleti Nokwazi Nkwinika Was A Year Into Her Master’s Dissertation In English, And She Was Struggling.

A degree with a difference: using South African sign language instead of the written word
This Masters degree sets a precedent in South Africa and gives universities that want to be truly inclusive a lot to think about.

Nyeleti Nokwazi Nkwinika was a year into her Master’s dissertation in English, and she was struggling. This has nothing to do with her work ethic: the problem lay with her hearing. Nyeleti was born deaf and like many others in her situation, she battles with written language.

Most deaf people are born into hearing families who don’t have any skills in Sign Language. In Nyeleti’s case, she only learned to use South African Sign Language fluently at school. When she got to high school she attended a mainstream hearing school with several other top performing deaf pupils from her previous school.

By then, she had missed out on too many years of access to English. South African Sign Language and English are differently structured. This can make it hard to learn for deaf people who’ve only ever used sign language to communicate. It’s also very difficult to learn written English when one has never heard the language or used it for conversational purposes.

More Posts from Philosophical-amoeba and Others

7 years ago

I am 100% convinced that “exit, pursued by a bear” is a reference to some popular 1590s meme that we’ll never be able to understand because that one play is the only surviving example of it.


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7 years ago

The Okinawan Language

Anybody who has studied Japanese and Linguistics will know that Japanese is a part of the Japonic language family. For many years it was thought that Japanese was a language isolate, unrelated to any other language (Although there is some debate as to whether or not Japanese and Korean are related). Today, most linguists are in agreement that Japanese is not an isolate. The Japonic languages are split into two groups: Japanese (日本語) and its dialects, which range from standard Eastern Japanese (東日本方言) to the various dialects found on Kyūshū (九州日本方言), which are, different, to say the least. The Ryukyuan Languages (琉球語派). Which are further subdivided into Northern and Southern Ryukyuan languages. Okinawan is classified as a Northern Ryukyuan Languages. There are a total of 6 Ryukyuan languages, each with its own dialects. The Ryukyuan languages exist on a continuum, somebody who speaks Okinawan will have a more difficult time understanding the Yonaguni Language, which is spoken on Japan’s southernmost populated island. Japanese and Okinawan (I am using the Naha dialect of Okinawan because it was the standard language of the Ryukyu Kingdom), are not intelligible. Calling Okinawan a dialect of Japanese is akin to calling Dutch a dialect of English. It is demonstrably false. Furthermore, there is an actual Okinawan dialect of Japanese, which borrows elements from the Okinawan language and infuses it with Japanese. So, where did the Ryukyuan languages come from? This is a question that goes hand in hand with theories about where Ryukyuan people come from. George Kerr, author of Okinawan: The History of an Island People (An old book, but necessary read if you’re interested in Okinawa), theorised that Ryukyuans and Japanese split from the same population, with one group going east to Japan from Korea, whilst the other traveled south to the Ryukyu Islands. “In the language of the Okinawan country people today the north is referred to as nishi, which Iha Fuyu (An Okinawn scholar) derives from inishi (’the past’ or ‘behind’), whereas the Japanese speak of the west as nishi. Iha suggests that in both instances there is preserved an immemorial sense of the direction from which migration took place into the sea islands.” (For those curious, the Okinawan word for ‘west’ is いり [iri]). But, it must be stated that there are multiple theories as to where Ryukyuan and Japanese people came from, some say South-East Asia, some say North Asia, via Korea, some say that it is a mixture of the two. However, this post is solely about language, and whilst the relation between nishi in both languages is intriguing, it is hardly conclusive. With that said, the notion that Proto-Japonic was spoken by migrants from southern Korea is somewhat supported by a number of toponyms that may be of Gaya origin (Or of earlier, unattested origins). However, it also must be said, that such links were used to justify Japanese imperialism in Korea. Yeah, when it comes to Japan and Korea, and their origins, it’s a minefield. What we do know is that a Proto-Japonic language was spoken around Kyūshū, and that it gradually spread throughout Japan and the Ryukyu Islands. The question of when this happened is debatable. Some scholars say between the 2nd and 6th century, others say between the 8th and 9th centuries. The crucial issue here, is the period in which proto-Ryukyuan separated from mainland Japanese. “The crucial issue here is that the period during which the proto-Ryukyuan separated(in terms of historical linguistics) from other Japonic languages do not necessarily coincide with the period during which the proto-Ryukyuan speakers actually settled on the Ryūkyū Islands.That is, it is possible that the proto-Ryukyuan was spoken on south Kyūshū for some time and the proto-Ryukyuan speakers then moved southward to arrive eventually in the Ryūkyū Islands.” This is a theory supported by Iha Fuyu who claimed that the first settlers on Amami were fishermen from Kyūshū. This opens up two possibilities, the first is that ‘Proto-Ryukyuan’ split from ‘Proto-Japonic’, the other is that it split from ‘Old-Japanese’. As we’ll see further, Okinawan actually shares many features with Old Japanese, although these features may have existed before Old-Japanese was spoken. So, what does Okinawan look like? Well, to speakers of Japanese it is recognisable in a few ways. The sentence structure is essentially the same, with a focus on particles, pitch accent, and a subject-object-verb word order. Like Old Japanese, there is a distinction between the terminal form ( 終止形 ) and the attributive form ( 連体形 ). Okinawan also maintains the nominative function of nu ぬ (Japanese: no の). It also retains the sounds ‘wi’ ‘we’ and ‘wo’, which don’t exist in Japanese anymore. Other sounds that don’t exist in Japanese include ‘fa’ ‘fe’ ‘fi’ ‘tu’ and ‘ti’. Some very basic words include: はいさい (Hello, still used in Okinawan Japanese) にふぇーでーびる (Thank you) うちなー (Okinawa) 沖縄口 (Uchinaa-guchi is the word for Okinawan) めんそーれー (Welcome) やまとぅ (Japan, a cognate of やまと, the poetic name for ‘Japan’) Lots of Okinawan can be translated into Japanese word for word. For example, a simple sentence, “Let’s go by bus” バスで行こう (I know, I’m being a little informal haha!) バスっし行ちゃびら (Basu sshi ichabira). As you can see, both sentences are structured the same way. Both have the same loanword for ‘bus’, and both have a particle used to indicate the means by which something is achieved, ‘で’ in Japanese, is ‘っし’ in Okinawan. Another example sentence, “My Japanese isn’t as good as his” 彼より日本語が上手ではない (Kare yori nihon-go ga jouzu dewanai). 彼やか大和口ぬ上手やあらん (Ari yaka yamatu-guchi nu jooji yaaran). Again, they are structured the same way (One important thing to remember about Okinawan romanisation is that long vowels are represented with ‘oo’ ‘aa’ etc. ‘oo’ is pronounced the same as ‘ou’). Of course, this doesn’t work all of the time, if you want to say, “I wrote the letter in Okinawan” 沖縄語で手紙を書いた (Okinawa-go de tegami wo kaita). 沖縄口さーに手紙書ちゃん (Uchinaa-guchi saani tigami kachan). For one, さーに is an alternate version of っし, but, that isn’t the only thing. Okinawan doesn’t have a direct object particle (を in Japanese). In older literary works it was ゆ, but it no longer used in casual speech. Introducing yourself in Okinawan is interesting for a few reasons as well. Let’s say you were introducing yourself to a group. In Japanese you’d say みんなさこんにちは私はフィリクスです (Minna-san konnichiwa watashi ha Felixdesu) ぐすよー我んねーフィリクスでぃいちょいびーん (Gusuyoo wan’nee Felix di ichoibiin). Okinawan has a single word for saying ‘hello’ to a group. It also showcases the topic marker for names and other proper nouns. In Japanese there is only 1, は but Okinawan has 5! や, あー, えー, おー, のー! So, how do you know which to use? Well, there is a rule, typically the particle fuses with short vowels, a → aa, i → ee, u → oo, e → ee, o → oo, n → noo. Of course, the Okinawan pronoun 我ん, is a terrible example, because it is irregular, becoming 我んねー instead of  我んのー or 我んや. Yes. Like Japanese, there are numerous irregularities to pull your hair out over! I hope that this has been interesting for those who have bothered to go through the entire thing. It is important to discuss these languages because most Ryukyuan languages are either ‘definitely’ or ‘critically’ endangered. Mostly due to Japanese assimilation policies from the Meiji period onward, and World War 2. The people of Okinawa are a separate ethnic group, with their own culture, history, poems, songs, dances and languages. It would be a shame to lose something that helps to define a group of people like language does. I may or may not look in the Kyūshū dialects of Japanese next time. I’unno, I just find them interesting.


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7 years ago
Barefoot To School… Clogher, Co Tyrone, Ireland, From The Rose Shaw Collection

Barefoot to school… Clogher, Co Tyrone, Ireland, from the Rose Shaw collection


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8 years ago

Largest Batch of Earth-size, Habitable Zone Planets

Our Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.

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This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.

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Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

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This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.

All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

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At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.

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In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.

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For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.

The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.

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 The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.

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The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.

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Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer. 

How Did the Spitzer Space Telescope Detect this System?

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system. 

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Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.

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The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.

At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like: 

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Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com


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7 years ago

Do you any tips about using ms paint?

I think I have few tips

#1Use 500x500 px or bigger canvas size. Any smaller size will make a brush look messy and shit.Here look:

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Can you see the difference?? Lineart in 600x600 px is so much smoother

#2

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#3

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#4 RIGHT MOUSE BUTTON YOU NEED IT

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#5

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*:・゚✧it’s like manga : *✧・゚

that’s all tbh

i hope this was somewhat helpful 


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7 years ago

Molecule of the Day: Chloroform

Molecule Of The Day: Chloroform
Molecule Of The Day: Chloroform

Chloroform (CHCl3) is a colourless, dense liquid that is immiscible with water at room temperature and pressure. Popularised by movies and dramas, it is often cited as an incapacitating agent in popular culture.

Chloroform was used as a general anaesthetic due to its ability to depress the central nervous system, a property that was discovered in 1842. This produced a medically-induced coma, allowing surgeons to operate on patients without them feeling any pain.

Molecule Of The Day: Chloroform

However, chloroform was found to be associated with many side effects, such as vomiting, nausea, jaundice, depression of the respiratory system, liver necrosis and tumour formation, and its use was gradually superseded in the early 20th century by other anaesthetics and sedatives such as diethyl ether and hexobarbital respectively.

Molecule Of The Day: Chloroform

While chloroform has been implicated in several criminal cases, its use as an incapacitating agent is largely restricted to fiction; the usage of a chloroform-soaked fabric to knock a person out would take at least 5 minutes.

Chloroform is metabolised in the liver to form phosgene, which can react with DNA and proteins. Additionally, phosgene is hydrolysed to produced hydrochloric acid. These are believed to cause chloroform’s nephrotoxicity.

Chloroform is often used as a reagent to produce dichlorocarbene in situ via its reaction with a base like sodium tert-butoxide. This is a useful precursor to many derivatives. For example, the dichlorocarbene can be reacted with alkenes to form cyclopropanes, which can be difficult to synthesise otherwise.

Molecule Of The Day: Chloroform

Chloroform is industrially synthesised by the free radical chlorination of methane:

CH4 + 3 Cl2 –> CHCl3 + 3 HCl

It can also be synthesised by the reaction of acetone with sodium hypochlorite in bleach by successive aldol-like reactions:

Molecule Of The Day: Chloroform

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7 years ago
In Slow Motion, Vortex Rings Can Be Truly Stunning. This Video Shows Two Bubble Rings Underwater As They

In slow motion, vortex rings can be truly stunning. This video shows two bubble rings underwater as they interact with one another. Upon approach, the two low-pressure vortex cores link up in what’s known as vortex reconnection. Note how the vortex rings split and reconnect in two places – not one. According to Helmholtz’s second theorem a vortex cannot end in a fluid–it must form a closed path (or end at a boundary); that’s why both sides come apart and together this way. After reconnection, waves ripple back and forth along the distorted vortex ring; these are known as Kelvin waves. Some of those perturbations bring two sides of the enlarged vortex ring too close to one another, causing a second vortex reconnection, which pinches off a smaller vortex ring. (Image source: A. Lawrence; submitted by Kam-Yung Soh)

Note: As with many viral images, locating a true source for this video is difficult. So far the closest to an original source I’ve found is the Instagram post linked above. If you know the original source, please let me know so that I can update the credit accordingly. Thanks!


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8 years ago

The code that took America's Apollo 11  to the moon in the 1960's has been published

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

When programmers at the MIT Instrumentation Laboratory set out to develop the flight software for the Apollo 11 space program in the mid-1960s, the necessary technology did not exist. They had to invent it.

They came up with a new way to store computer programs, called “rope memory,” and created a special version of the assembly programming language. Assembly itself is obscure to many of today’s programmers—it’s very difficult to read, intended to be easily understood by computers, not humans. For the Apollo Guidance Computer (AGC), MIT programmers wrote thousands of lines of that esoteric code.

Here’s a very 1960s data visualization of just how much code they wrote—this is Margaret Hamilton, director of software engineering for the project, standing next to a stack of paper containing the software:

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

The AGC code has been available to the public for quite a while–it was first uploaded by tech researcher Ron Burkey in 2003, after he’d transcribed it from scanned images of the original hardcopies MIT had put online. That is, he manually typed out each line, one by one.

“It was scanned by an airplane pilot named Gary Neff in Colorado,” Burkey said in an email. “MIT got hold of the scans and put them online in the form of page images, which unfortunately had been mutilated in the process to the point of being unreadable in places.” Burkey reconstructed the unreadable parts, he said, using his engineering skills to fill in the blanks.

  “Quite a bit later, I managed to get some replacement scans from Gary Neff for the unreadable parts and fortunately found out that the parts I filled in were 100% correct!” he said.

As enormous and successful as Burkey’s project has been, however, the code itself remained somewhat obscure to many of today’s software developers. That was until last Thursday (July 7), when former NASA intern Chris Garry uploaded the software in its entirety to GitHub, the code-sharing site where millions of programmers hang out these days.

Within hours, coders began dissecting the software, particularly looking at the code comments the AGC’s original programmers had written. In programming, comments are plain-English descriptions of what task is being performed at a given point. But as the always-sharp joke detectives in Reddit’s r/ProgrammerHumor section found, many of the comments in the AGC code go beyond boring explanations of the software itself. They’re full of light-hearted jokes and messages, and very 1960s references.

One of the source code files, for example, is called BURN_BABY_BURN--MASTER_IGNITION_ROUTINE, and the opening comments explain why:

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

About 900 lines into that subroutine, a reader can see the playfulness of the original programming team come through, in the first and last comments in this block of code:

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

In the file called LUNAR_LANDING_GUIDANCE_EQUATIONS.s, it appears that two lines of code were  meant to be temporary ended up being permanent, against the hopes of one programmer:

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

In the same file, there’s also code that appears to instruct an astronaut to “crank the silly thing around.”

The Code That Took America's Apollo 11  to The Moon In The 1960's has Been published

“That code is all about positioning the antenna for the LR (landing radar),” Burkey explained. “I presume that it’s displaying a code to warn the astronaut to reposition it.”

And in the PINBALL_GAME_BUTTONS_AND_LIGHTS.s file, which is described as “the keyboard and display system program … exchanged between the AGC and the computer operator,” there’s a peculiar Shakespeare quote:

This is likely a reference to the AGC programming language itself, as one Reddit user . The language used predetermined “nouns” and “verbs” to execute operations. The verb pointed out 37, for example, means “Run program,” while the noun 33 means “Time to ignition.”

Now that the code is on GitHub, programmers can actually suggest changes and file issues. And, of course, they have


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8 years ago

Neutrinos Hint of Matter-Antimatter Rift

Neutrinos Hint Of Matter-Antimatter Rift

the same underground observatory in Japan where, 18 years ago, neutrinos were first seen oscillating from one “flavor” to another — a landmark discovery that earned two physicists the 2015 Nobel Prize — a tiny anomaly has begun to surface in the neutrinos’ oscillations that could herald an answer to one of the biggest mysteries in physics: why matter dominates over antimatter in the universe.

The anomaly, detected by the T2K experiment, is not yet pronounced enough to be sure of, but it and the findings of two related experiments “are all pointing in the same direction,” said Hirohisa Tanaka of the University of Toronto, a member of the T2K team who presented the result to a packed audience in London earlier this month.

“A full proof will take more time,” said Werner Rodejohann, a neutrino specialist at the Max Planck Institute for Nuclear Physics in Heidelberg who was not involved in the experiments, “but my and many others’ feeling is that there is something real here.”

The long-standing puzzle to be solved is why we and everything we see is matter-made. More to the point, why does anything — matter or antimatter — exist at all? The reigning laws of particle physics, known as the Standard Model, treat matter and antimatter nearly equivalently, respecting (with one known exception) so-called charge-parity, or “CP,” symmetry: For every particle decay that produces, say, a negatively charged electron, the mirror-image decay yielding a positively charged antielectron occurs at the same rate. But this cannot be the whole story. If equal amounts of matter and antimatter were produced during the Big Bang, equal amounts should have existed shortly thereafter. And since matter and antimatter annihilate upon contact, such a situation would have led to the wholesale destruction of both, resulting in an empty cosmos.

Somehow, significantly more matter than antimatter must have been created, such that a matter surplus survived the annihilation and now holds sway. The question is, what CP-violating process beyond the Standard Model favored the production of matter over antimatter?

Many physicists suspect that the answer lies with neutrinos — ultra-elusive, omnipresent particles that pass unfelt through your body by the trillions each second.

To that end, starting in 2010, scientists with the T2K experiment generated beams of neutrinos or antineutrinos in Tokai, Japan, and aimed them toward the Super-Kamiokande neutrino observatory, a sensor-lined tank of 50,000 tons of pure water located nearly 200 miles away in Kamioka. Occasionally, these ghostly particles interacted with atoms inside the water tank, generating detectable flashes of radiation. Detecting a difference in the behavior of the neutrinos and antineutrinos would provide an important clue about the preponderance of matter over antimatter, perhaps opening up a route beyond the Standard Model to a more complete theory of nature. Already, the strange properties of neutrinos provide a possible outline of that fuller story.

Neutrinos Hint Of Matter-Antimatter Rift

Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo At the Super-Kamiokande observatory in Kamioka, Japan — shown here when it was being filled with water in 2006 — neutrinos interact with atoms inside the water, generating flashes of radiation that are picked up by the surrounding sensors.

Primordial Neutrinos

The 1998 discovery that neutrinos switch flavors on the fly “may change our most fundamental theories,” President Bill Clinton said at the time, “from the nature of the smallest subatomic particles to how the universe itself works.”

Neutrino oscillations defied the Standard Model’s prediction that the particles are massless, like photons. In order for neutrinos to oscillate, each of their three possible flavors (electron, muon and tau) must be a quantum-mechanical mixture, or “superposition,” of three possible masses. Quantum superpositions evolve over time. So a neutrino might start out with its three mass components giving it pure muon flavor, but as the components evolve at different rates, electron flavor gradually enters the mixture, and the neutrino will have some probability of being measured as an electron neutrino.

There’s no mechanism within the Standard Model by which neutrinos might acquire their tiny, nonzero masses. Also unknown is why all neutrinos are observed to be “left-handed,” spinning clockwise with respect to their direction of motion, while all antineutrinos are right-handed, spinning counterclockwise.

Experts overwhelmingly favor a double-duty explanation of neutrino mass and single-handedness called the “seesaw mechanism,” whereby the known, lightweight, left-handed neutrinos have much heavier right-handed counterparts, and the known antineutrinos likewise have superheavy left-handed counterparts (the light and heavy masses are inversely related, like two sides of a seesaw). For this seesaw explanation to work, the neutrinos and antineutrinos on each side of the seesaw must actually be the same particle, except for their opposite handedness. Numerous experiments are now hunting for an extremely rare radioactive decay that would confirm this “Majorana” nature of neutrinos, thereby shoring up the logic of the seesaw mechanism.

If the theory is correct, then the heavy neutrinos and antineutrinos would have populated the hot young universe, when there was enough energy to beget beastly particles. They would have since decayed. Physicists wonder: Might their decays have produced the matter-antimatter asymmetry? This is the question to which an answer may be emerging — and much sooner than expected.

Tilted Seesaw

There’s good reason to think that neutrinos violate CP symmetry. The one established instance of CP violation in the laws of physics arises among the quarks — the building blocks of protons and neutrons — whose flavor mixing is described by a mathematical matrix similar to the one for neutrino mixing. In the quark case, though, the value of a numerical factor in the matrix that creates a disparity between quarks and antiquarks is very small. Quarks and antiquarks behave far too symmetrically to account for the universe’s matter-antimatter imbalance.

Neutrinos Hint Of Matter-Antimatter Rift

Lucy Reading-Ikkanda for Quanta Magazine

But the neutrino mixing matrix comes equipped with its own factor by which neutrinos and antineutrinos can violate CP symmetry. (Paradoxically, they can behave differently from one another even if they are Majorana particles, identical except for their opposite handedness.) If the lightweight neutrinos and antineutrinos violate CP symmetry, then the hypothetical heavy primordial neutrinos and antineutrinos must as well, and their asymmetric decays could easily have produced the universe’s glut of matter. Discovering CP violation among the lightweight neutrinos “will boost that general framework,” said Neal Weiner, a theoretical physicist at New York University.

The question is, how large will the CP-violation factor be? “The fear was that it would be small,” said Patricia Vahle, a physicist at the College of William & Mary — so small that the current generation of experiments wouldn’t detect any difference between neutrinos’ and antineutrinos’ behavior. “But it is starting to look like maybe we will be lucky,” she said.

To search for CP violation, the T2K scientists looked for evidence that neutrinos and antineutrinos oscillated between muon and electron flavors with unequal probabilities as they traveled between Tokai and Kamioka. The amount of CP violation once again works like a seesaw, with the rate of muon-to-electron neutrino conversions on one side, and corresponding antineutrino conversions on the other. The larger the value of the factor in the matrix, the greater the seesaw’s tilt.

If the seesaw is balanced, signifying perfect CP symmetry, then (accounting for differences in the production and detection rates of neutrinos and antineutrinos) the T2K scientists would have expected to detect roughly 23 electron neutrino candidates and seven electron antineutrino candidates in Kamioka, Tanaka said. Meanwhile, if CP symmetry is “maximally” violated — the seesaw tilted fully toward more neutrino oscillations and fewer antineutrino oscillations — then 27 electron neutrinos and six electron antineutrinos should have been detected. The actual numbers were even more skewed. “What we observed are 32 electron neutrino candidates and four electron antineutrino candidates,” Tanaka said.

With so few total events, it’s too soon to know whether the apparent tilt of the seesaw, signifying a large amount of CP violation, is real or a statistical aberration. Two other new hints of CP violation, however, strengthen the case. First, the newly running NOvA experiment, which generates a beam of muon neutrinos in Illinois and measures electron neutrinos in Minnesota, found a large number of these oscillations, again suggesting that the seesaw may be tilted in favor of neutrino oscillations and away from antineutrino oscillations. Second, researchers at the Super-Kamiokande observatory detected a similar enhancement of electron neutrinos coming from Earth’s atmosphere. (T2K and NOvA both plan to submit their findings for publication later this year.)

Vahle, who presented NOvA’s new results this month in London, urged caution; even when the T2K and NOvA results are combined, their statistical significance remains at a low level known as “2 sigma,” where there’s still a 5 percent chance the apparent deviation from CP symmetry is a random fluke. The results “do give me hope that finding CP violation in neutrino oscillations won’t be as hard as many feared it would be,” she said, “but we aren’t there yet.”

If CP violation among neutrinos is real and as large as it currently seems, then the evidence will slowly strengthen in the coming years. T2K’s signal could reach 3-sigma significance by the mid-2020s. “It’s a very exciting time as we look forward to a lot more data from both experiments,” said Peter Shanahan, a NOvA co-spokesperson.

It isn’t yet known exactly how CP violation in the light neutrino oscillations would translate into CP-violating decays of the heavy set. But discovering the former would point physicists in the latter’s general direction. “If we are starting to see [CP violation] in the neutrino sector, it is certainly a critical result,” Weiner said.

Story from Quanta Magazine

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7 years ago
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 
Dublin Streetscapes From 1900 (John J. Clarke Collection) 

Dublin streetscapes from 1900 (John J. Clarke collection) 


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philosophical-amoeba - Lost in Space...
Lost in Space...

A reblog of nerdy and quirky stuff that pique my interest.

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