We need to completely rewrite the textbooks on how to teach teachers

September 10th, 2018

We need to completely rewrite the textbooks on how to teach teachers:

That’s according to a new report just published by the National Council on Teacher Quality. The report describes a vast and severe failure of teacher-training courses and the textbooks that accompany them to convey evidence-based practices; while delivering unsupported anecdotal evidence and well-debunked myths in spades. The report is accompanied by a letter of support signed by an assortment of professors of psychology and learning sciences from universities around the world.

The report finds that out of 48 texts used in teacher-training programs none accurately described fundamental evidence-based teaching strategies comprehensively. Only 15 percent had more than a single page devoted to evidence-based practices; the remainder contained either zero or only a few sentences on methods that have been backed up by the decades of scientific findings that exist in the field of educational psychology.

Missing from these textbooks were detailed explanations of six core strategies that have been found to be backed by evidence, which every teacher should know and use. The strategies aren’t new; they were identified by the Institute of Education Sciences, the research arm of the U.S. Department of Education, as being the most effective techniques in all classrooms regardless of age or subject in guidance released in 2007.

Six Core Strategies Identified by Institute of Education Sciences

Hamsters really do love wheels

September 9th, 2018

Like other rodents, hamsters are highly motivated to run in wheels:

It is not uncommon to record distances of 9 km (5.6 mi) being run in one night. Other 24-h records include 43 km (27 mi) for rats, 31 km (19 mi) for wild mice, 19 km (12 mi) for lemmings, 16 km (9.9 mi) for laboratory mice, and 8 km (5.0 mi) for gerbils.

Hypotheses to explain such high levels of running in wheels include a need for activity, substitute for exploration, and stereotypic behaviour. However, free wild mice will run on wheels installed in the field, which speaks against the notion of stereotypic behaviour induced by captivity conditions. Alternatively, various experimental results strongly indicate that wheel-running, like play or the endorphin or endocannabinoid release associated with the ‘runner’s high’, is self-rewarding. Wheel use is highly valued by several species as shown in consumer demand studies which require an animal to work for a resource, i.e. bar-press or lift weighted doors. This makes running wheels a popular type of enrichment to the captivity conditions of rodents.

Captive animals continue to use wheels even when provided with other types of enrichment. In one experiment, Syrian hamsters that could use tunnels to access five different cages, each containing a toy, showed no more than a 25% reduction in running-wheel use compared to hamsters housed in a single cage without toys (except for the running wheel).

In another study, female Syrian hamsters housed with a nest-box, bedding, hay, paper towels, cardboard tubes, and branches used a wheel regularly, and benefited from it as indicated by showing less stereotypic bar-gnawing and producing larger litters of young compared to females kept under the same conditions but without a wheel. Laboratory mice were prepared to perform more switch presses to enter a cage containing a running wheel compared to several meters of Habitrail tubing or a torus of Habitrail tubing.

Running in wheels can be so intense in hamsters that it may result in foot lesions, which appear as small cuts on the paw pads or toes. Such paw wounds rapidly scab over and do not prevent hamsters from continuing to run in their wheel.

A hamster in a running wheel equipped with a generator can generate up to 500 mW electric power, enough for illuminating small LED lamps.

(Hat tip to our Slovenian Guest.)

eSports update

September 8th, 2018

Tyler Cowen shares an eSports update:

Tournament prize pools now rival those for some of the biggest events in traditional sports, and global audiences for some big gaming events have surpassed 100 million viewers, driven largely by esports’ exploding popularity in Asia.

The lion’s share of esports revenue comes from corporate sponsorships, according to industry analysis firm Newzoo, with ticket sales, merchandising and broadcasting rights bringing in additional revenue. Newzoo estimates that esports will generate $345 million in revenue in North America this year, in addition to more than half a billion dollars in revenue overseas.

Commenter Stuart “worked in an earlier era of this business (2008)” and notes that “it is a weird world”:

A key challenge I perceived then as now is the opaque visible display of athleticism. The gap between a great tennis player and myself is quite easy to see. I can pick up a racket, but I can’t do much more. In contrast, I can play the same games as these pros and feel accomplished by virtue of a sliding scale of difficulty which games have relied on for decades. Certainly a youth league for Tennis offers a similar analogy to this, but games are designed to be winnable, creating some ambiguity about the difference between the average joe and the pros. The more one plays, the clearer the contrast becomes, but the level of understanding on the part of the general public to the nuance of this struck me then as the reason why it would not gain mass appeal.

What has happened in the intervening decade seems to be a continued disregard for any ‘mainstream’ audience but the continued development of a formerly niche viewership which can appreciate the nuance, strategy and skill on display.

Like other ‘nerdy’ pursuits, eSports still seem to wrestle with a hunger for mainstream acceptance (e.g. lobbying for inclusion in the Olympics), but are clearly at their best when speaking to their core, which is growing by the year.

As another commenter noted, the incentives are unusual in eSports, where a developer owns the game. “Imagine what the NFL would do differently if they were trying to maximize the number of people playing football instead of the number of people watching football.”

Scientists identify a new kind of human brain cell

September 7th, 2018

Scientists have identified a new kind of human brain cell:

The research team, co-led by Lein and Gábor Tamás, Ph.D., a neuroscientist at the University of Szeged in Szeged, Hungary, has uncovered a new type of human brain cell that has never been seen in mice and other well-studied laboratory animals.

Tamás and University of Szeged doctoral student Eszter Boldog dubbed these new cells “rosehip neurons” — to them, the dense bundle each brain cell’s axon forms around the cell’s center looks just like a rose after it has shed its petals, he said. The newly discovered cells belong to a class of neurons known as inhibitory neurons, which put the brakes on the activity of other neurons in the brain.

The study hasn’t proven that this special brain cell is unique to humans. But the fact that the special neuron doesn’t exist in rodents is intriguing, adding these cells to a very short list of specialized neurons that may exist only in humans or only in primate brains.

The researchers don’t yet understand what these cells might be doing in the human brain, but their absence in the mouse points to how difficult it is to model human brain diseases in laboratory animals, Tamás said. One of his laboratory team’s immediate next steps is to look for rosehip neurons in postmortem brain samples from people with neuropsychiatric disorders to see if these specialized cells might be altered in human disease.

Every specimen is arguably irreplaceable

September 6th, 2018

Brazil’s National Museum in Rio de Janeiro burned down, which is terrible, but not terribly surprising:

The burned building was the largest natural-history museum in Latin America, but it had never been completely renovated in its 200-year history. It had long suffered from obvious infrastructure problems including leaks, termite infestations, and — crucially — no working sprinkler system. Recognizing these problems in the 1990s, museum staff began planning to move the collection into a different site, but without stable funding, those plans proceeded in fits and starts.

[...]

The museum’s herbarium, its main library, and some of its vertebrates were housed in a different building that was untouched by the fire. But together, these reportedly account for just 10 percent of the museum’s collection. For comparison, the remaining 90 percent includes twice as many specimens as the entire British Museum. Museum staff carried out whatever they could by hand, including parts of the mollusk collection. Time will tell what else survived, and some losses are already clear: The floor beneath the entomology collection collapsed, for example, and the 5 million butterflies and other arthropods within were likely lost.

The museum’s archeological collection had frescoes from Pompeii, and hundreds of Egyptian artifacts, including a 2,700-year-old painted sarcophagus. It housed art and ceramics from indigenous Brazilian cultures, some of whose populations number only in their thousands. It contained audio recordings of indigenous languages, some of which are no longer spoken; entire tongues went up in flames. It carried about 1,800 South American artifacts that dated back to precolonial times, including urns, statues, weapons, and a Chilean mummy that was at least 3,500 years old.

Older still was the museum’s rich trove of fossils, from crocodile relatives like Pepesuchus to one of the oldest relatives of today’s scorpions. It harbored some of the oldest human remains in the Americas: the 11,500-year-old skull and pelvis of a woman who was unearthed in 1975 and nicknamed Luzia. “The skull is very fragile,” the artist Maurilio Oliveira told The New York Times. “The only thing that could have saved it is if a piece of wood or something fell and protected it.”

One might think that fossils, being rock, would be immune to fire. But as Mariana Di Giacomo, a paleontologist from the University of Delaware, described in a Twitter thread, fires can reach temperatures that are high enough to crack stone. It destroys buildings, causing walls and ceilings to fall on fragile specimens. It burns the labels attached to fossils and the numbers that are painted onto them, turning something that’s part of the scientific record into uninformative rock. “Without data, we only have old bones/shells/logs,” wrote Di Giacomo. Even the water that’s used to quench the flames can make things worse, causing fossils to swell and crack, dissolving adhesives, ruining labels even further, and stimulating the growth of mold.

The burned building housed skeletons of several dinosaurs, including Maxakalisaurus, a 44-foot-long, armor-backed, long-necked titan, and Santanaraptor, a lithe predator that contained beautifully preserved soft tissues in its legs, down to individual muscle fibers. “That really stabs me in the heart as a scientist,” said John Hutchinson from the Royal Veterinary College. “I always wanted to go study that specimen. It could have been revelatory. Now that probably will be impossible for anyone.”

The museum was also home to an irreplaceable collection of pterosaurs — flying reptiles that soared over the dinosaurs’ heads. Brazil was something of a “heaven for pterosaurs,” and the discovery of spectacular creatures such as Tapejara, Tupandactylus, and Tupuxuara, with their marvelously complete skeletons and improbably ornate crests, helped to reshape our understanding of these animals. “We may have lost dozens of the best preserved pterosaurs in the world,” said the paleontologist Mark Witton. “There really is no collection comparable … We find them elsewhere in the world, but the quality of the Brazilian material is remarkable.”

Many of these presumably lost specimens were holotypes — the first, best, and most important examples of their kind. Every specimen is arguably irreplaceable, but holotypes are especially so. Losing them is like losing the avatar of an entire species. Some of these specimens have been drawn and described in the scientific literature, but that information is often patchy, which is why scientists frequently return to holotypes to study them with their own eyes.

I’m reminded of all the Middle Eastern artifacts housed in London — where they’re a good deal safer.

Bulk metallic glasses can be readily extruded and 3D-printed

September 5th, 2018

The 3-D printing of thermoplastics is highly advanced, but the 3-D printing of metals is still challenging and limited:

The reason being that metals generally don’t exist in a state that they can be readily extruded.

“We have shown theoretically in this work that we can use a range of other bulk metallic glasses and are working on making the process more practical and commercially-usable to make 3-D printing of metals as easy and practical as the 3-D printing of thermoplastics,” said Prof. Schroers.

Unlike conventional metals, bulk metallic glasses (BMGs) have a super-cooled liquid region in their thermodynamic profile and are able to undergo continuous softening upon heating — a phenomenon that is present in thermoplastics, but not conventional metals. Prof. Schroers and colleagues have thus shown that BMGs can be used in 3-D printing to generate solid, high-strength metal components under ambient conditions of the kind used in thermoplastic 3-D printing.

The new work could side-step the obvious compromises in choosing thermoplastic components over metal components, or vice-versa, for a range of materials and engineering applications. Additive manufacturing of metal components has been developed previously, where a powder bed fusion process is used, however this exploits a highly-localized heating source, and then solidification of a powdered metal shaped into the desired structure. This approach is costly and complicated and requires unwieldy support structures that are not distorted by the high temperatures of the fabrication process.

The approach taken by Prof. Schroers and colleagues simplifies additive manufacturing of metallic components by exploiting the unique-amongst-metals softening behavior of BMGs. Paired with this plastic like characteristics are high strength and elastic limits, high fracture toughness, and high corrosion resistance. The team has focused on a BMG made from zirconium, titanium, copper, nickel and beryllium, with alloy formula: Zr44Ti11Cu10Ni10Be25. This is a well-characterized and readily available BMG material.

The team used amorphous rods of 1 millimeter (mm) diameter and of 700mm length. An extrusion temperate of 460 degrees Celsius is used and an extrusion force of 10 to 1,000 Newtons to force the softened fibers through a 0.5mm diameter nozzle. The fibers are then extruded into a 400°C stainless steel mesh wherein crystallization does not occur until at least a day has passed, before a robotically controlled extrusion can be carried out to create the desired object.

(Hat tip to Jonathan Jeckell.)

Fitbit heart data reveals its secrets

September 3rd, 2018

Fitbit has now logged 150 billion hours’ worth of heart-rate data from tens of millions of people, all over the world:

Fitbit Heart Data 1 Resting Heart Rate by Age

Fitbit Heart Data 2 BMI vs. HR by Gender

Fitbit Heart Data 3 Resting Heart Rate with Exercise

Fitbit Heart Data 4 Activity Effect on Resting Heart Rate by Age

Fitbit Heart Data 5 Resting Heart Rate with Sleep

Fitbit Heart Data 6 Activity vs. Heart Rate by Country

Missile lock-on!

August 31st, 2018

I was listening to the audio version of David Suarez’s techno-thriller Kill Decision, when the pilot of the good guys’ C-130 announced “missile lock-on!” How exactly does missile lock-on work, and how does the target know it’s locked on?

Aircraft radars typically have two modes: search and track. In search mode, the radar sweeps a radio beam across the sky in a zig-zag pattern. When the radio beam is reflected by a target aircraft, an indication is shown on the radar display. In search mode, no single aircraft is being tracked, but the pilot can usually tell generally what a particular radar return is doing because with each successive sweep, the radar return moves slightly.

[...]

In track mode, the radar focuses its energy on a particular target. Because the radar is actually tracking a target, and not just displaying bricks when it gets a reflection back, it can tell the pilot a lot more about the target.

[...]

An important thing to note is that a radar lock is not always required to launch weapons at a target. For guns kills, if the aircraft has a radar lock on a target, it can accurately gauge range to the target, and provide the pilot with the appropriate corrections for lead and gravity drop, to get an accurate guns kill. Without the radar, the pilot simply has to rely on his or her own judgement.

[...]

And what about missiles? Again, a radar lock is not required. For heat-seeking missiles, a radar lock is only used to train the seeker head onto the target. Without a radar lock, the seeker head scans the sky looking for “bright” (hot) objects, and when it finds one, it plays a distinctive whining tone to the pilot. The pilot does not need radar in this case, he just needs to maneuver his aircraft until he has “good tone,” and then fire the missile. The radar only makes this process faster.

Now, radar-guided missiles come in two varieties: passive and active. Passive radar missiles do require a radar lock, because these missiles use the aircraft’s reflected radar energy to track the target.

Active radar missiles however have their own onboard radar, which locks and tracks a target. But this radar is on a one-way trip, so it’s considerably less expensive (and less powerful) than the aircraft’s radar. So, these missiles normally get some guidance help from the launching aircraft until they fly close enough to the target where they can turn on their own radar and “go active.” (This allows the launching aircraft to turn away and defend itself.) It is possible to fire an active radar missile with no radar lock (so-called “maddog”); in this case, the missile will fly until it’s nearly out of fuel, and then it will turn on its radar and pursue the first target it sees. This is not a recommended strategy if there are friendly aircraft in close proximity to the enemy.

[...]

Radar is just radio waves, and just as your FM radio converts radio waves into sound, so can an aircraft analyze incoming radio signals to figure out who’s doing what. This is called an RWR, or radar warning receiver, and has both a video and audio component.

[...]

Each time a new radar signal is detected, it is converted into an audio wave and played for the pilot. Because different radars “sound” different, pilots learn to recognize different airborne or surface threats by their distinctive tones. The sound is also an important cue to tell the pilot what the radar is doing: If the sound plays once, or intermittently, it means the radar is only painting our aircraft (in search mode). If a sound plays continuously, the radar has locked onto our aircraft and is in track mode, and thus the pilot’s immediate attention is demanded. In some cases, the RWR can tell if the radar is in launch mode (sending radar data to a passive radar-guided missile), or if the radar is that of an active radar-guided missile. In either of these cases, a distinctive missile launch tone is played and the pilot is advised to immediately act to counter the threat. Note that the RWR has no way of knowing if a heat-seeking missile is on its way to our aircraft.

Who cares how much carbon dioxide is on Mars?

August 30th, 2018

The whole argument over how much carbon dioxide is on Mars now is totally irrelevant, since we need to import far, far more nitrogen to terraform the planet:

The surface pressure on Mars now averages about 0.6 percent of our own sea level pressure, or about 0.087 psi (600 pascals), and is thus a “physiological vacuum”. This means the pressure is less than a tenth of the “Armstrong Limit” of about 0.9 psi (6,200 pascals) where blood boils and far below what is needed to survive even with pure oxygen. You would need to wear a pressure suit to survive on the surface, just like on the Moon. Fortunately, though chilly, the temperatures on Mars are much milder than those on the Moon.

In addition, the surface of Mars is exposed to about 250 millisieverts (mSv) per Earth year of solar and galactic (cosmic) radiation, composed partly of dangerous high-speed atomic nuclei that can leave a trail of dead brain cells behind. Due to these particles, cosmic radiation is more dangerous than “regular” radiation. Crews and early civilian settlers would need to live underground in heavily shielded, pressurized habitat buildings to prevent the cosmic ray nuclei from reaching them. For reference, you would experience some radiation sickness if you got a dose of 1000 mSv all at once. In interplanetary space, you would get about 657 mSv per year without shielding, but on Mars, the planet itself blocks half of the radiation and the thin atmosphere absorbs another 20 percent of what remains. At this lower but constant rate, you would not get sick but there would be cumulative cell damage and a slow increase in cancer risk. On Earth, at sea level, we have in effect a layer of air equivalent in mass to 10.3 meters of water over our heads, which absorbs virtually all of the dangerous high-energy particles. On Mars, that layer is equivalent to about 20 centimeters of water, barely enough to shield anyone from a dangerous solar “proton storm” radiation outburst.

So there are three main reasons we need significant air pressure on Mars: to remove the need for pressure suits when working outside (and so that we would no longer need to live in pressurized habitats), to allow water to exist as a liquid on the surface, and to block the ubiquitous cosmic radiation so that buildings can be right on the surface and so that people can work on the surface without being irradiated. We can look at this issue from two points of view: radiation blocking mass and air pressure. So how much air mass and pressure do we really need?

From the radiation perspective, this is primarily a matter of sheer mass. On Earth at sea level, we have enough air over our heads so that only a tiny fraction of the natural background radiation most people get per year, totaling 3 to 6 mSv, is from space. To duplicate that very good level of protection on Mars requires a comparable amount of air mass (10.3 metric tons) over every square meter of Mars surface, ignoring the great altitude differences. Multiply this by the number of square meters of Mars surface and you get the required air mass: 1.493 trillion metric tons. This amount would create about 6.14 psi of air pressure or about 0.42 of Earth sea level pressure. More importantly, essentially all of the dangerous cosmic radiation from space would be blocked. This compares to the paltry 25 trillion metric tons of air currently in place at Mars, almost all of it CO2.

Some may note that for the same air column mass (the mass of air over a given surface area), we are not getting as much air pressure as we do on Earth. With Mars lower gravity, about 38% of Earths, it takes more air mass per square meter than it does on Earth to produce the same amount of pressure. So with the radiation threat now (theoretically) dealt with, how much air pressure do we need and what kind?

Right now, the air you are breathing is about 78 percent nitrogen and only about 21 percent oxygen. Carbon dioxide is a trace gas, at only 0.04 percent. You actually breathe 25 times more argon than carbon dioxide. If you are old enough, or are a space history buff, you may remember the Apollo 1 fire. The first Apollo spacecraft being prepared to be launched with a crew had about 16 psi of pure oxygen inside it during a pre-launch test, and all of the metal and plastic surfaces were saturated with oxygen. The capsule interior was like a fire bomb waiting for one tiny spark. The three astronauts were quickly asphyxiated by smoke within a minute of that spark and most of the interior of the capsule was incinerated. This horrific accident illustrates how dangerous high levels of oxygen are.

So future colonists would have little use for an atmosphere of almost all carbon dioxide, and they would not want an atmosphere mostly of oxygen due to the huge fire risk it would create. It turns out that the oxygen in any future nitrogen-oxygen atmosphere should be less than 50 percent of the total air pressure, but with the 42 percent pressure described above, we would still need a future 50-50 oxygen and nitrogen mix. (The amount of nitrogen delivered should be related to the future oxygen component.) So if we increase the air column mass to about 12.3 metric tons over each meter of surface, we get almost exactly half sea level pressure, or about 7.35 psi. To create this half-atmosphere of pressure (almost all of nitrogen) we need to add 1,784 trillion tons of nitrogen. However, this is equivalent to an altitude on Earth of about 5,200 meters, the altitude of the highest community on Earth in the Andes.

We assume, once we have a half-atmosphere of pressure, early settlers would be using oxygen helmets when working outside, and living inside slightly pressurized habitats, which could then be on the surface, with a nitrogen-oxygen mix. In addition, those in charge of the terraforming process would want to find ways to slowly add oxygen to the atmosphere, such as using the oxygen in some of the carbon dioxide and the existing water on Mars. This may take a long time, but adding oxygen will also add to the atmospheric pressure. Eventually, perhaps after centuries, there would be enough oxygen to breath and green plants could grow outside, but not so much as to be dangerous. A reasonable mix at about 10 psi would obviously be 70 percent nitrogen and 30 oxygen oxygen, providing the needed 3 psi of oxygen. This would be similar to being at about 3,000 meters on Earth, which the majority of people can obviously tolerate. For example, the town of Leadville, Colorado, is at an altitude of 3,100 meters. This is why we want the nitrogen in place first as it is a non-reactive gas.

Wait, I have a question:

Now, of course, many people will wonder where do we get all of these trillions of tons of nitrogen to import onto Mars. The planet has very little of it: just a few percent of what is needed, as most of it was lost during the last 3.5 billion years. However, It turns out that the outer solar system has huge amounts of nitrogen, both as a gas, such as on Titan, and as a semi-solid slush or ice on Pluto, Triton, and very probably the other large Kuiper Belt dwarf planets. Small asteroids would not have significant amounts of nitrogen as their gravity would have been too low to hold an atmosphere. We should be able to mine some of this nitrogen and move it to Mars where it can help support life. The current atmospheric loss rate from Mars would be very low.

Right now, it is true we have no means of moving the nitrogen, but chances are, with the new private investments in fusion power, that we will have it before we are ready to start terraforming. Fusion rocket powered tugs would only need to thrust for a few days to a couple weeks to send huge loads of nitrogen—as much as 100 million tons in each load—into the inner solar system at low speeds and carefully intersect the atmosphere of Mars. Ten such loads would deliver a billion tons of nitrogen, as much mass as a cubic kilometer of water, and 10,000 loads would deliver a full trillion tons.

The image at the top of this article shows a load of 100,000 chunks of nitrogen (shown as cubes but they could be in huge plastic bags.) Each chunk is about 10 meters across and weighs about 1,000 tons. By aiming these large loads of nitrogen ice so that they come in exactly horizontally at the high atmosphere of Mars over the desired areas, instead of impacting on Mars surface, there are no craters formed and all of the nitrogen is turned into gas and added to the atmosphere over an entry path of hundreds of kilometers. Very large amounts of heat, but no dangerous radiation, are created by these entries, which would occur many times a day and go on for over 100 years.

The entries could be targeted over the ice caps or glaciers and would easily melt them totally, as each entry produces as much radiant heat as a hydrogen bomb but with no dangerous radiation. Thus, the ice cap melting can be done by these repeated entry events, instead of a few, very dangerous cratering events. The fusion tugs back away from their loads before entry and head back to the outer solar system at high speed since they now have no load. Climatologists may have to hurry to get valuable ice cores of all the ice cap areas before they are melted to form a new, but initially shallow, Boreal Ocean and other bodies of water.

Easy-peasy then!

Everything about Stratolaunch is supersized

August 29th, 2018

Everything about Stratolaunch is supersized:

It has six screaming Pratt & Whitney turbofan jet engines, salvaged from three 747s. Its maximum takeoff weight is 1.3 million pounds. It’s got more than 80 miles of wiring. Most astounding is its 385-foot wingspan, the spec that puts Stratolaunch in the history books.

Stratolaunch

One problem with ground-based rockets is that they can take off from only a small number of facilities, like the Kennedy Space Center or Vandenberg Air Force Base, where competition for launch time creates long delays. A plane-based launch would create new possibilities.

But a plane that big had other challenges. Rutan’s analysis concluded that to deliver the weight of the rocket Elias was talking about—up to 640,000 pounds—you’d need a wingspan of almost 400 feet. That wing had to be strong too. In addition to two fuselages and tons of fuel, it would be carrying a set of jet engines and that massive vehicle. Rutan planned to build the plane from nonmetal composites, rather than aluminum, to keep the weight down, but making the composite strong enough presented another problem. Rutan solved this dilemma in part with a process called pultrusion, in which a machine pulls a material at a constant rate and then bakes it until it hardens, a way to mold huge segments of the plane with a consistent strength. This technique let the engineers manufacture the very long spars that fortify the giant wing.

Rutan began working on a design, even as he realized that the odds were against it ever being built. Using traditional construction methods and materials, the price tag might stretch past a billion, perhaps even reaching the cost of a nuclear aircraft carrier. He figured he could build it more cheaply, especially if he took his scavenger mentality to the limit. “I reasoned that if I could lift out engines, pylons, landing gear, actuators, electricals, and cockpit stuff from 747s, it was doable for us,” he says.

[...]

The team worked to speed up construction by using off-the-shelf parts whenever possible, the most conspicuous example being the repurposing of three 747s. But the surface of the plane had to be created from scratch. “This vehicle has some of the largest composite components ever built in the world, made by hand by fabricators, all made by our guys,” says Jacob Leichtweisz­-Fortier, who works on the plane. The most massive pieces were 285-foot spars that give the wing its resiliency, each one weighing 18,000 pounds. The team first constructed the wing out of the gargantuan spars and built the rest of the plane around it.

The plane’s extreme size led to some unexpected complications: The scaffolding needed to assemble the wing had to be about 40 feet high. “It starts to look like a building,” Stinemetze says. “In fact, the way California treats it, it is a building. It has to meet codes for sprinklers and electrical power.” When the plane was ready to emerge from its scaffolding and get towed out of the hangar, just lowering it 2 feet to the ground took eight hours, Floyd says.

[...]

Sharing their road map publicly for the first time, Thornburg and Floyd laid out their plans for Stratolaunch: Its first custom rocket ship will be considerably bigger than the Pegasus, able to transport multiple satellites or other payloads. This medium-size rocket is nicknamed Kraken, after the legendary Icelandic sea monster. Floyd says customers will be able to use it to get satellites into low Earth orbit for less than $30 million, a competitive price and about half of what SpaceX charges for a launch of its Falcon 9 rocket. Floyd estimates that Kraken will be operational in 2022.

Release the Kraken!

Collaborate on complex problems, but only intermittently

August 28th, 2018

A new study suggests that teams should collaborate on complex problems, but only intermittently:

Bernstein, Assistant Professor Jesse Shore of the Questrom School of Business at Boston University, and Professor David Lazer of Northeastern University put together and studied a number of three-person groups performing a complex problem-solving task. The members of one set of groups never interacted with each other, solving the problem in complete isolation; members of another set constantly interacted, as we do when equipped with always-on technologies; and members of the third set of groups interacted only intermittently.

From prior research, the researchers anticipated that the groups whose members never interacted would be the most creative, coming up with the largest number of unique solutions — including some of the best and some of the worst — and a high level of variation that sprang from their working alone. In short, they expected the isolated individuals to produce a few fantastic solutions but, as a group, a low average quality of solution due to the variation. That proved to be the case.

The researchers also anticipated that the groups whose members constantly interacted would produce a higher average quality of solution, but fail to find the very best solutions as often. In other words, they expected the constantly interacting groups’ solutions to be less variable but at the cost of being more mediocre. That proved to be the case as well.

But here’s where the researchers found something completely new: Groups whose members interacted only intermittently preserved the best of both worlds, rather than succumbing to the worst. These groups had an average quality of solution that was nearly identical to those groups that interacted constantly, yet they preserved enough variation to find some of the best solutions, too.

Perhaps the most interesting result was that when their interactions were intermittent, the higher performers were able to get even better by learning from the low performers. When high and low performers interacted constantly, the low performers tended to simply copy high performers’ solutions and were in turn generally ignored by the high performers. But when their interactions were intermittent, the low performers’ ideas helped the high performers achieve even better solutions.

Bernstein and his co-authors see a number of workplace implications for these findings, including the advantages of alternating independent efforts with group work over a period of time. In some ways, that’s how work traditionally has been done in organizations — with individuals working alone, then coming together in a meeting, then returning to work alone. But advancing technology has changed those cycles.

A Golden Era of live-action sitcoms for six-year-olds

August 27th, 2018

If you are a mid-Baby Boomer born in the late 1950s, Steve Sailer suggests, you probably have a memory of the mid-1960s as a Golden Era of live-action sitcoms for six-year-olds, such as Gilligan’s Island, Get Smart, Adams Family, Munsters, Green Acres, I Dream of Jeannie, and Bewitched:

It’s not clear if it really was a halcyon era or if all six-year-olds look back fondly on the TV shows when they were six. In the defense of the former view, I don’t recall that many animated shows from the same era. (I was a big fan of Johnny Quest, though.)

I think it’s plausible that a lot of money and talent poured into sitcoms in 1964-65, creating a brief period of shows that appealed both to grown-ups and kids. Bewitched, for instance, started out as a relatively straightforward study of the sociological stresses of a mixed marriage. (Marrying a shiksa was a huge theme looming just below the surface in 1960s TV, although in Bewitched the allegory is kept ambiguous. Elizabeth Montgomery, for example, was the daughter of Hollywood Republican stalwart Robert Montgomery.) But the network kept demanding more goofy magic For the Kids.

The latter two shows involved ladies in mixed (magical/human) relationships who use magic to get their housekeeping chores done (a concept that greatly appealed to my future wife at the time), while the man of the house disapproves of the woman taking unfair advantage of her powers to make his life better, but the woman knows best what he really needs.

Also, both magical ladies have relatives who disapprove of the man of the house, such as Darren’s mother-in-law Endora (Agnes Moorhead), brunette evil twin Serena (Elizabeth Montgomery in a dual role), and Uncle Arthur (Paul Lynde — I was surprised to see the memorable Lynde only appeared in 10 of the 254 episodes).

If you’re a bit younger than Sailer, you probably remember all the shows from that Golden Era of live-action sitcoms for six-year-olds as childhood favorites, only in reruns.

Anyway, Sailer was spurred to write about this after reading about a potential Bewitched remake from Black-ish creator Kenya Barris:

In Bewitched, written by Barris and Taylor, Samantha, a hardworking black single mom who happens to be a witch, marries Darren, a white mortal who happens to be a bit of a slacker. They struggle to navigate their differences as she discovers that even when a black girl is literally magic, she’s still not as powerful as a decently tall white man with a full head of hair in America.

Sigh.

Call it moxie

August 27th, 2018

Gregory Clark finds that social status is strongly heritable, and Gregory Cochran runs with this:

Combined with a very high degree of assortative mating for the genetic factors behind this heritability, social mobility is surprisingly low. This happens without anyone particularly trying to make it this way — although it can happen less if people do try to stop it. An interesting example out of Plomin’s group: genetics explains “twice as much variance in educational attainment and occupational status in the post-Soviet era compared with the Soviet era.”

Plomin (or maybe more exactly his student Kaili Rimfeld) says that “The extent of genetic influence on these social outcomes can be viewed as an index of success in achieving meritocratic values of equality of opportunity by rewarding talent and hard work, which are to a large extent influenced by genetic factors, rather than rewarding environmentally driven privilege. ”

I don’t think that statement is entirely wrong. Estonia today is better run than it was in 1953, or 1990. But I am just as sure that it isn’t entirely right. We’re talking about genetic factors that tend to increase social status: intelligence helps, sure, but the people at the top, the people running the show are rarely the smartest — or the most decent, or the most effective. If we define ‘merit’ as a tendency to effective action that favors the best interest of society as a whole — surely what high-status people have more of is only loosely associated with ‘merit’. They have more of what works for themselves. Call it moxie.

So the ideal social policy would attempt — and succeed — at picking people for high-status job that were good at getting the job done — not just good at getting the job. Talent and hard work are influenced by genetic factors, but then so is being a back-stabbing, credit-stealing asshole.

I don’t think it would be easy: nature’s agin it. But it’s possible. I think. To a degree.

What should the Classical Greeks have done with Alcibiades, who surely had enough genetic moxie for a platoon? Answer: shoot the bastard. Him better off dead.

Its aerial roots drip with a thick, clear, glistening mucus that’s loaded with bacteria

August 26th, 2018

Corn, or maize, originated in southern Mexico, when it was domesticated from a wild cereal called teosinte, and the region is still home to the greatest diversity of the crop, including a unique variety that uses air as fertilizer:

For thousands of years, people from Sierra Mixe, a mountainous region in southern Mexico, have been cultivating an unusual variety of giant corn. They grow the crop on soils that are poor in nitrogen — an essential nutrient — and they barely use any additional fertilizer. And yet, their corn towers over conventional varieties, reaching heights of more than 16 feet.

A team of researchers led by Alan Bennett from UC Davis has shown that the secret of the corn’s success lies in its aerial roots — necklaces of finger-sized, rhubarb-red tubes that encircle the stem. These roots drip with a thick, clear, glistening mucus that’s loaded with bacteria. Thanks to these microbes, the corn can fertilize itself by pulling nitrogen directly from the surrounding air.

Aerial roots of corn from Sierra Mixe

The Sierra Mixe corn takes eight months to mature — too long to make it commercially useful. But if its remarkable ability could be bred into conventional corn, which matures in just three months, it would be an agricultural game changer.

All plants depend on nitrogen to grow, and while there’s plenty of the element in the air around us, it’s too inert to be of use. But bacteria can convert this atmospheric nitrogen into more usable forms such as ammonia — a process known as fixation. Legumes, like beans and peas, house these nitrogen-fixing bacteria in their roots. But cereals, like corn and rice, largely don’t. That’s why American farmers need to apply more than 6.6 million tons of nitrogen to their corn crops every year, in the form of chemical sprays and manure.

Incentives boost effort on IQ tests

August 25th, 2018

Will intelligence test-taking performance increase if people are paid $75 to do well on the test? James Thompson takes a look:

This is an interesting question, because critics of intelligence testing have argued that some groups get low scores because they are not interested in the test, and can’t see the point of solving the problems. Perhaps so, although if you don’t get motivated by trying to solve problems that might be diagnostic in itself.

Gilles Gignac decided to have a look at this argument, seeing whether the offer of winning $75 Australian dollars boosted intelligence test scores in university students. For once, I am not too bothered by the subjects being university students, because they tend to have modest funds and healthy appetites.

[...]

The financial incentive was observed to impact test-taking effort statistically significantly. By contrast, no statistically significant effects were observed for the intelligence test performance scores.

[...]

One reason why test-taking motivation is correlated with intelligence test scores may be that bright people like solving problems. If they have to take a test, they look forward to it, knowing they usually do well, and are interested in finding out precisely how well they do. Less able students don’t like tests, and particularly get discouraged when they relate to difficult subjects.