Hearing test, radiation-resistant cells, sign language and more

Curious Bends is a weekly newsletter about science, tech., data and India. Akshat Rathi and I curate it. You can subscribe to it here. If have feedback, suggestions, or would just generally like to get in touch, just email us.

1. Poor children deserve better hearing tests; an Indian entrepreneur may have the solution

An estimated 63 million people in India suffer from hearing problems. But children are not tested for such impairment at a young age because of the costs of testing. Early detection and intervention is crucial for improving the difficulties with cognition and language skills. Now, a Bangalore-based inventor has come up with a solution that sharply lowers the cost of testing if a newborn can hear properly. (3 min read)

2. What makes cells resistant to radiation?

Radiation can damage cell’s DNA, and sometimes make them cancerous. But not all cells are affected by such radiation. Previously, it was thought that such ability was down to the DNA repair mechanisms in place in every one of them, but a new study shows that cells have more weapons to fight this invisible attack. (2 min read)

3. What sign language teaches us about the brain

As she took a course to learn sign language, a question kept nagging this neurobiologist: does the brain treat the visual language differently from spoken languages? Turns out, for the most part, they don’t. And yet brain studies of deaf people who use sign language helps bust a few myths about how our brains work. (5 min read)

+ The author of this piece, Sana Suri, is a neurobiologist at the University of Oxford.

4. Another biotech startup accelerator opens up in Bangalore. Can it deliver?

India’s biotech industry is supposed to be undergoing a boom. It was projected that revenues would reach $5 billion by 2009, but that hasn’t happened yet. Industry watchers remain optimistic, claiming that revenues will reach $100 billion by 2020. Can a startup accelerator help achieve this dream? (5 min read)

5. BRICS can boost their research by setting up collaborations, but there seems to be no will

The recent BRICS summit in Brazil saw the launch of the New Development Bank, which has been setup to rival the World Bank and the International Monetary Fund. But there was little progress on setting aside joint funds to boost scientific collaboration. There is a huge potential here but no one is interested in tapping it. (2 min read)

Chart of the week

It has been a terrible week for the civilian aviation industry with Malaysia Airlines Flight 17 shot down over Ukraine and an ongoing investigation of Air Algerie Flight 5017 that crashed in Mali. Vasudevan Mukunth (one of the curators of Curious Bends; a.k.a. me) has collected the data of all such past events in one interactive chart.

screen-shot-2014-07-26-at-11-35-28-e1406399183451

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Science Quiz – July 28, 2014

Every week, I create a science quiz for The Hindu newspaper’s In School product. It consists of 10 questions and only developments from the week preceding its day of publication (Monday). The answers are at the end.

  1. What’s a haboob?
  2. American biologists tracked ____ ______ over 15 years. On July 25, they announced that their species could be protected from collisions from ships moving in waters along the western coast of North America, contributing to their long-term survival. Fill in the blanks.
  3. In the last last two decades, over 1,500 planets outside the Solar System have been found. In the week of July 21, 2014, astronomers said that life on these planets would find it easier to evolve if they had ______, which would keep surface temperatures from varying too much between day and night. Fill in the blank with the name of a visible object found commonly in Earth’s atmosphere, with types like uncinus, spissatus, nebulosus, congestus, etc.
  4. Researchers who were studying the behavior of dogs found that man’s best friends also experience ________ like humans do, implying that this emotion may not require complex minds. Fill in the blank.
  5. Paleontologists have found 70-million year old footprints of ____________ ___ in Canada. The prints show three pairs of limbs moving parallel to each other, suggesting that these reptiles might have hunted in packs. Fill in the blanks with the name of a dinosaur whose name in Latin means “king lizard”.
  6. If a group of scientists from America and France are to be believed, the evolution of the sizes and shapes of human-made airplanes are mimicking the evolution of the sizes and shapes of what?
  7. According to a report published on July 22, 2014, which animal (with the nomenclature Loxodanta africana) has the world’s most sensitive nose, possessing over 2,000 genes to sense smells (as opposed to humans’ about 400)?
  8. The spots on a _____ _______ are masked by their black fur, making it harder to tell them apart or document their numbers. According to National geographic, however, these animals are less rare than supposed, having been found to be particularly common in the Anshi-Dandeli tiger reserve, Karnataka. Fill in the blanks.
  9. Twenty years ago, in July 1994, the comet Shoemaker-Levy 9 broke apart and collided with the _______, providing the astronomers with their first chance to observe to two extraterrestrial bodies colliding within the Solar System. The comet is also unique because it was found to be orbiting the planet instead of the Sun. Fill in the blank with the name of the planet.
  10. July 25 was the 94th birth anniversary of this British biophysicist who made great important contributions to the study of molecular structures. Around 1953, she helped James Watson and Francis Crick discover the double-helix sructure of DNA, a watershed moment in the history of molecular biology. Name her.

Answers

  1. An intense dust storm that occurs in arid regions of the world, also known as a sandstorm. They are carried by winds moving into a thunderstorm.
  2. Blue whales
  3. Clouds
  4. Jealousy
  5. Tyrannosaurus rex
  6. Birds
  7. African bush elephant
  8. Black panther
  9. Jupiter
  10. Rosalind Franklin

No country for new journalism

(Formatting issues fixed.)

TwitterNgoodThrough an oped in Nieman Lab, Ken Doctor makes a timely case for explanatory – or explainer – journalism being far from a passing fad. Across the many factors that he argues contribute to its rise and persistence in western markets, there is evidence that he believes explainer journalism’s historical basis is more relevant than its technological one, most simply by virtue of having been necessitated by traditional journalism no longer connecting the dots well enough.

Second, his argument that explainer journalism is helped by the success of digital journalism takes for granted the resources that have helped it succeed in the west and not so much in countries like India.

So these points make me wonder if explainer journalism can expect to be adopted with similar enthusiasm here – where, unsurprisingly, it is most relevant. Thinking of journalism as an “imported” enterprise in the country, differences both cultural and historical become apparent between mainstream English-language journalism and regional local-language journalism. They cater to different interests and are shaped by different forces. For example, English-language establishments cater to an audience whose news sources are worldwide, who can always switch channels or newspapers and not be worried about running out of options. For such establishments, How/Why journalism is a way to differentiate itself.

Local v. regional

On the other hand, local-language establishments cater to an audience that is not spoiled for options and that is dependent profoundly on Who/What/When/Where journalism no matter where its ‘reading diaspora’. For them, How/Why journalism is an add-on. In this sense, the localism that Ken Doctor probes in his piece has no counterpart. It is substituted with a more fragmented regionalism whose players are interested in an expanding readership over that of their own scope. In this context, let’s revisit one of his statements:

Local daily newspapers have traditionally been disproportionately in the Who/What/When/Where column, but some of that now-lost local knowledge edged its ways into How/Why stories, or at least How/Why explanations within stories. Understanding of local policy and local news players has been lost; lots of local b.s. detection has vanished almost overnight.

Because of explainer journalism’s reliance on digital and digital’s compliance with the economics of scale (especially in a market where purchasing power is low), what Doctor calls small, local players are not in a position to adopt explainer journalism as an exclusive storytelling mode. As a result of this exclusion, Doctor argues that what digital makes accessible – i.e. what is found online – often lacks the local angle. But it remains to be seen if this issue’s Indian counterpart – digital vs. the unique regional as opposed to digital vs. the small local - is even likely to be relevant. In other words, do smaller regional players see the need to take the explainer route?

Local-level journalism (not to be confused with what is practiced by local establishments) in India is bifocal. On the one hand, there are regional players who cover the Who/What/When/Where thoroughly. On the other, there are the bigger English-language mainstreamers who don’t each have enough reporters to cover a region like India thanks, of course, to its profuse fragmentation, compensating instead by covering local stories in two distinct ways:

  1. as single-column 150-word pieces that report a minor story (Who/What/When/Where) or
  2. as six-column 1,500-word pieces where the regional story informs a national plot (How/Why),

—as if regional connect-the-dots journalism surfaces as a result of mainstream failures to bridge an acknowledged gap between conventional and contextualizing journalism. Where academicians, scholars and other experts do what journalists should have done – rather, in fact, they help journalists do what they must do. Therefore, readers of the mainstream publications have access to How/Why journalism because, counter-intuitively, it is made available in order to repair its unavailability. This is an unavailability that many mainstreamers believe they have license to further because they think the ‘profuse fragmentation’ is an insurmountable barrier.

There’s no history

The Hindu and The Indian Express are two Indian newspapers that have carved a space for themselves by being outstanding purveyors of such How/Why journalism, and in the same vein can’t be thought of as having succumbed to the historical basis that makes the case for its revival—“Why fix something that ain’t broken?”. And the “top-drawer” publications such as The New York Times and The Washington Post that Doctor mentions that find a need to conspicuously assert this renewal are doing so on the back of the technology that they think has finally made the renewal economically feasible. And that the Times stands to be able to charge a premium for packaging Upshot and its other offerings together is not something Hindu or Express can also do now because, for the latter couple, How/Why isn’t new, hasn’t been for some time.

Therefore, whereupon the time has come in the western mainstream media to “readopt” explainer journalism, its Indian counterpart can’t claim to do that any time soon because it has neither the west’s historical nor technological bases. Our motivation has to come from elsewhere.

Dying in a finite universe

In his book Infinite In All Directions (2002), Freeman Dyson, one of the tallest intellectual giants of our times, attempts to rescue eschatology from the specious grip of religion and teleology with a mix of scientific reasoning and informed speculation. During this, when describing the big crunch, which is one way our universe could end, he moves smoothly from the rational track he has been sprinting on to a less exact but more pertinent and romantic description. In his words,

There is a great melancholy in the picture of a finite universe, its force spent, its days of passion over, counting the hours remaining before it slides into oblivion. What will our last poets sing, whoever they may be, human or alien, as they watch the stars crowding together and streaming faster and faster across the imploding sky? Perhaps in their final moments they will remember the words of our contemporary, Ivor Gurney, echoing down the eons from the springtime of our species:

The songs I had are withered
or vanished clean,
Yet there are bright tracks
Where I have been,
And there grow flowers
For others’ delight.
Think well, O singer,
Soon comes night.

I wonder if the universe will make this transition just as seamlessly, and the twilight of starstuff will prove to be just as pleasing, should it happen. Then again, to share Dyson’s conviction is to embrace naturalism for that’s all the beauty that we will see, and there is hope that it will be inexhaustible. Again, in his words and from the same book,

No matter how far we go into the future, there will always be new things happening, new information coming in, new worlds to explore, a constantly expanding domain of life, consciousness and memory.

Kepler data reveals a frost giant

I’ve been most fascinated lately by studies of planet formation. Every small detail is like that one letter in the crossword you need to fill all the other boxes in, every discovery a cornerstone that holds together a unique piece of the universe. For example, using just the find that the exoplanet Beta Pictoris b has a very short day of eight hours, astronomers could speculate on how it was formed, what its density could be, and how heavy it could get over time. And it isn’t surprising if a similar tale awaits telling by Kepler 421b, an exoplanet some 1,000 ly from Earth toward the constellation Lyra. Its discovery was reported on July 17, a week ago. And its pièce de résistance is that it has a long year, i.e. orbital period, of 704 days.

Illustrating the transit technique. The technique applies only when the planet can be seen head on against the background of its star. Image: http://www2.ifa.hawaii.edu/

Illustrating the transit technique. The Kepler telescope looks for the drop in brightness in its search for exoplanets. The technique applies only when the planet can be seen head on against the background of its star. Image: http://www2.ifa.hawaii.edu/

To have such a long year, it must be orbiting pretty far from its star - Kepler 421 – which in turn should’ve made it hard to discover. The NASA Kepler space telescope spots exoplanets by looking for the dip in a star’s brightness as the planet moves in front of it, called a transit. Because of Kepler 421b’s high orbital period, it transited its central star only twice in the four years Kepler was looking at it. Together with its orbital eccentricity – i.e. how elliptic its orbit is – Kepler had only a 0.3% chance of spotting it on its way around the star. In fact, 421b has the longest year for any known exoplanet discovered using the transit technique. This means we need to start considering if the M.O. isn’t good enough to spot exoplanets with large orbital periods, a class of planets that astronomers have been looking for. On the other hand, now that 421b has been spotted and studied to some extent, astronomers can form impressions of its history and future.

The frost line

For starters, they were able to deduce the planet’s size based on how much starlight it blocked and the shape of its orbit from how much light it blocked during each full transit. The readings point to 421b being like Uranus, with radius four times Earth’s, density at least 5 g/cc, and an eccentric orbit. Being like Uranus also means a surface temperature of -90 degrees Celsius (183 kelvin). This is plausible because 421b is 1.2 times as far from its star as Earth is from the Sun, and its star is a dimmer orange dwarf.

These wintry conditions are found beyond a star’s frost line, an imaginary line marking the distance beyond which space is cold enough to cause hydrogen-based molecules to condense into icy grains. So planets orbiting beyond this distance are also icy. Kepler 421b is likely the first exoplanet astronomers have found (using the transit technique) orbiting a star beyond its frost line. In other words, this might be our first exoplanet that’s an ice giant – “might” because 421b hasn’t been independently observed yet.

Not surprisingly, the frost line also marks a more significant boundary in terms of planet formation. Though observations made by Kepler are starting to show that the Solar System is a surprisingly unique planetary system, it’s still the one we understand best and use to analogize what we finds in other worlds. Astronomers believe planets in the system formed out of a disk of matter surrounding a younger Sun. The inner Earth-like (telluric) planets formed when rocky matter started to clump together and “fall out” of this disk. The outer gaseous planets, beyond the frost line, formed when icy grains stuck together to form watery planetary embryos.

In this artist's conception, gas and dust-the raw materials for making planets-swirl around a young star. The planets in our solar system formed from a similar disk of gas and dust captured by our sun. Credit: NASA/JPL-Caltech

In this artist’s conception, gas and dust-the raw materials for making planets-swirl around a young star. The planets in our solar system formed from a similar disk of gas and dust captured by our sun. Credit: NASA/JPL-Caltech

The prevailing belief is that planets take at least three million years to form. In the same period, the central star is also evolving – in this case, Kepler 421 is a K-class star becoming brighter – and the amount of material available in the protoplanetary disk is diminishing because planets are feeding off it. Consequently, the frost line is on the move. Calculations by the astronomers who discovered 421b find the exoplanet to be now where the system’s frost line might’ve been three million years ago.

The sedate giant

Right now, we’ve a lot of letters in the crossword. Piecing them together, we can learn the following:

  1. If a beyond-the-frost-line gas giant is as big as Uranus but not as big as Jupiter, it’s possible that not enough material was available when it started to form, rendering it a latecomer in the system
  2. The abundance of material required to form Jupiter-sized planets makes smaller worlds likelier than larger ones, and in fact implies worlds like 421b should be less unique than Kepler makes it seem (a 2013 study cited by the discoverers suggests that there might actually be a pile-up of planets transiting at the frost line of their stars)
  3. If the planet had to have formed behind its star’s frost line, and the frost line was three million years ago where the planet is now, the planet could be around three million years old – assuming it hasn’t moved around since forming
  4. 421b is very Uranus-like; if it has to be a rocky world, its mass has to be 60 times Earth’s, pointing at an improbably massive protoplanetary disk within one or two AU of a star – something we’re yet to find

#3 warrants a comparison with the Solar System’s history, especially Jupiter’s. Jupiter didn’t form where it is right now, having possibly moving toward and away from the Sun as a result of gravitational interactions with other planets that were forming. During its journeys, its own gravitational pull could’ve tugged on asteroid belts and other free-floating objects, pulling them out of one location and depositing them in another. Contrarily, 421b appears to have been far more sedate, probably not having moved at all due to its youth and isolation. If only it had moved inward, like Jupiter eventually did, its orbital period would’ve been shorter and Kepler would’ve have spotted it easier.

The confusion Jupiter might've caused during its journey through a nascent Solar System. Image: http://www.astro.washington.edu/courses/astro557/GrandTack2.pdf

The confusion Jupiter might’ve caused during its journey through a nascent Solar System. Image: http://www.astro.washington.edu/courses/astro557/GrandTack2.pdf

Another comparison can be made with Beta Pictoris b, the other exoplanet mentioned at the beginning of this piece, the one with the eight-hour-long days. Younger planets spin faster because they still have the angular momentum they acquired while accumulating mass before slowing down in time. Heavier planets also spin faster because they have more angular momentum to conserve. Similarly, we might be able to find out more about Kepler 421b’s past by uncovering its spin rate and getting a better estimate of its mass.

Anyway, a simple piecing together of facts and possibilities tells us – at least me – this much. Astronomers have one more awesome fact to take away: as the finders of 421b write in their pre-print paper, “the first member of this missing class of planets” has been found, and that means more astronomy to look forward to!


References

Discovery of a transiting planet near the snow line, Kipping et al, arXiv:1407.4807 (accepted in The Astrophysical Journal)

Finding quake shelters, breaking bad in Punjab, rice-wheat divide & more

Curious Bends is a weekly newsletter about science, tech., data and India. Akshat Rathi and I curate it. You can subscribe to it here. If have feedback, suggestions, or would just generally like to get in touch, just email us.

1. Pesticides may be to blame for some cancers among India’s farmers

The green revolution in India increased food production but the agrochemicals it used could also have set off a “cancer epidemic”. A three-year study by Punjabi University, Patiala, revealed no confounding factors across demographics except pesticides. Many patients, some of whom travel thousands of kilometers for affordable care, are from the revolution’s belt. (3 min read)

2. A socially cognizant tool to identify quake shelters

Nepali and German scientists have devised a method called Open Space Suitability Index to rank the suitability of public shelters that could be used as quake shelters. Uniquely for it, it assesses both physical and social vulnerability (that is, the risks people, businesses and governments face). (2 min read)

3. Spare the mafia, spoil the smuggler, dealer and consumer

Punjab has a drug problem. Despite widespread efforts by the state to blow it off, then blow it away, its Walter Whites and Jesse Pinkmans persist. One is a cop, the other might be a BSF jawan. Effectively, the Narcotics Control Bureau is lost for ideas, and it might be because the state is targeting the victims instead of the drug mafia. (29 min read)

+ The author of this piece, Ushinor Majumdar, is an ex-lawyer and a journalist with Tehelka.

4. Delayed survey derails health monitoring

As it is India lacks key data to better govern its people. Now, its main source of health statistics, the National Family Health Survey (NFHS), has been delayed. The NFHS is a large-scale household sample survey and produces internationally accepted estimates of fertility, mortality, contraceptive use, violence against women and, crucially, malnutrition. The latest survey should have been held in 2010, and it means for the last four years health workers have been blindsided. (2 min read)

5. Forget your 15 minutes of fame, think about your 15% chance of depression

Clinical depression has the dubious distinction of being the second most common cause of suffering in terms of burden of illness. The WHO has predicted it will become the leading cause of death by 2020. If this isn’t alarming, then sample this: new research says that every person in the world has a 15% chance of experiencing their first episode between the ages of 25 and 35. (4 min read)

Chart of the week

According to the 68th National Sample Survey (2011-2012), the consumption of rice has fallen marginally in a seven-year period while that of wheat is on the rise. There is a perceivable split between the Hindi heartland and the southern and eastern states which prefer wheat and rice, respectively. There is also an urban-rural and, intriguingly, a Jammu-Kashmir divide. Read more about it on Scroll.in.

1405378358-1351_Monthly-pc-qt-consumption-rice-urban

If you’re curious for more, follow Akshat and me on Twitter. Enjoy your week!

The new and large fly the farthest

British Airways and Air France mutually retired the Concorde supersonic jet in 2003. Both companies cited rising maintenance costs as being the reason, which in turn were compounded by falling demand after the Paris crash in 2000 and a general downturn in civil aviation after 9/11. Now, American and French scientists have found that Concorde was in fact an allometric outlier that stood out design-wise at the cost of its feasibility and, presumably, its maintenance. Perhaps it grounded itself.

One thing Adrian Bejan (Duke University), J.D. Charles (Boeing) and Sylvie Lorente (Toulouse University) seem to be in awe of throughout their analysis is that the evolution of commercial airplane allometry seems deterministic (allometry is the study of the relationship between a body’s physical dimensions and its properties and functions). This is awesome because it implies that the laws of physics used to design airplanes are passively guiding the designers toward very specific solutions in spite of creative drift, and that successive models are converging toward a sort of ‘unified model’. This paradigm sounds familiar because it could be said of any engineering design enterprise, but what sets it apart is that the evolution of airplane designs appears to be mimicking the evolution of flying animals despite significant anatomical and physiological differences.

One way to look at their analysis is in terms of the parameters the scientists claim have been guiding airplane design over the years:

  1. Wingspan
  2. Fuselage length
  3. Fuel load
  4. Body size

Among them, fuel load and body size are correlated along the lines of Tsiolkovsky’s rocket equation. It says that, for rockets, if two of the following three parameters are set, the third becomes immovably fixed in a proportional way: energy expenditure against gravity, potential energy in the propellant, and the fraction of the rocket’s mass made up by the propellant. According to Bejan et al, there is a corresponding ‘airplane equation’ that shows a similar correlation between engine size, amount of fuel, and mass of the whole vehicle. The NASA explainer finds this association tyrannical because, as Paul Gilster writes,

A … rocket has to carry more and more propellant to carry the propellant it needs to carry more propellant, and so on, up the dizzying sequence of the equation

Next, there is also a correlation between wingspan and fuselage length corresponding to an economy of scale such as what exists in nature. Bejan et al find that despite dissimilarities, airplanes and birds have evolved similar allometric rules on the road to greater efficiency, and that like bigger birds, bigger airplanes are “more efficient vehicles of mass”. Based on how different airplane components have evolved over the years, the scientists were able to distill a scaling relation.

S/L ~ M1/6 g1/2 ρ1/3 σ1/4aV2Cl)-3/4 21/4 Cf7/6

Be not afraid. S/L is the ratio of the wingspan to the fuselage length. It is most strongly influenced by ρa, the density; σ, the allowable stress level in the wing; g, the acceleration due to gravity; and Cf, the fixed skin-friction coefficient. More interestingly, the mass of the entire vehicle has a negligible effect on S/L, which pans out as a fixed S/L value across a range of airplane sizes.

Citation: J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

Citation: J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

Similarly, the size of a plane’s engine has also increased proportional to a plane’s mass. This would be common sense if not for there being a fixed, empirically determined correlation here as well: Me = 0.13M0.83, where Me and M are the masses of the engine and airplane, respectively, in tons.

During the evolution of airplanes, the engine sizes have increased almost proportionally with the airplane sizes (the data refer only to jet engine airplanes). J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

During the evolution of airplanes, the engine sizes have increased almost proportionally with the airplane sizes (the data refer only to jet engine airplanes). J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

In terms of these findings, the Concorde’s revolutionary design appears to have been a blip on the broader stream of traditional yet successful ones. In the words of the authors,

In chasing an “off the charts” speed rating the Concorde deviated from the evolutionary path traced by successful airplanes that preceded it. It was small, had limited passenger capacity, long fuselage, short wingspan, massive engines, and poor fuel economy relative to the airplanes that preceded it.

That the Concorde failed and that the creative drift it embodied couldn’t achieve what the uninspired rules that preceded it did isn’t to relegate the design of commercial airplanes to algorithms. It only stresses that whatever engineers have toyed with, some parameters have remained constant because they’ve had a big influence on performance. In fact, it is essentially creativity that will disrupt Bejan et al‘s meta-analysis by inventing less dense, stronger, smoother materials to build airplanes and their components with. By the analysts’ own admission, this is a materials era.

Bigger airplanes fly farther and are more efficient, and to maximize fuel efficiency, are becoming the vehicles of choice for airborne travel. And that there is a framework of allometric rules to passively maximize their inherent agency is a tribute to design’s unifying potential. In this regard, the similarity to birds persists (see chart below) as if to say there is only a fixed number of ways in which to fly better.

The characteristic speeds of all the bodies that fly, run, and swim (insects, birds, and mammals). J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

The characteristic speeds of all the bodies that fly, run, and swim (insects, birds, and mammals). J. Appl. Phys. 116, 044901 (2014); http://dx.doi.org/10.1063/1.4886855

From the paper:

Equally important is the observation that over time the cloud of fliers has been expanding to the right . In the beginning were the insects, later the birds and the insects, and even later the airplanes, the birds, and the insects. The animal mass that sweeps the globe today is a weave of few large and many small. The new are the few and large. The old are the many and small.


References

The evolution of airplanes, J. Appl. Phys. 116, 044901 (2014); DOI: 10.1063/1.4886855

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