Who are our Mexicans?

Wednesday, August 7th, 2013

Who are our Mexicans?, HBD Chick wondered, so she researched which Mexican states send the most immigrants to the US and then researched the history of their populations.

The Zacatecanos were considered chichimecas, or barbarians, by the Aztecs. Soldiers, Indians, and Silver: The Northward Advance of New Spain, 1550-1600 (pages 39, 46–48) has this to say:

The [Zacatecanos], tribesmen closest to most of the new silver mines, were the fourth nation of this Gran Chichimeca. They overlapped the land of the Guachichiles east and north of Zacatecas; they extended westward to border on the Tepehuanes near Durango; and they roamed as far north as Cuencame and Parras, where they touched upon the Irritilas or Laguna tribes. The [Zacatecanos] were mostly nomadic, although a few groups were essentially sedentary. They were brave and bellicose warriors and excellent marksmen. Some Spaniards called them the most valiant and warlike of all the Chichimecas. They were mightily feared by neighboring peoples, especially the Cazcanes, whom they attacked constantly — fifty [Zacatecanos] were known to have successfully raided a Cazcan pueblo of as many as three or four thousand inhabitants….

The general way of life throughout this Gran Chichimeca varied little from tribe to tribe and from nation to nation. Contemporary descriptions of the customs and characteristics of the Chichimecas seldom noted important variations between one grouping and another….

In hand-to-hand combat, the Chichimeca warrior gained, among other Indians and Spaniards, a reputation for courage and ferocity…. In fighting other Indians (Mexicans, Tarascans, Cazcanes), part of his courage could be accounted for by the contempt he felt for the tribes that had adopted the ways of the white man. And, as already implied, the Chichimeca came to have a lesser respect for the Spaniard himself as the Indian raids went unpunished….

[H]is contact with Spanish military practice also led the Chichimeca to take more practical measures to assure success in fighting. He sent spies into Spanish-Indian towns for appraisal of the enemy’s plans and strength; he developed a far-flung system of lookouts and scouts (*atalayas*); and, in major attacks, settlements were softened by preliminary and apparently systematic killing and stealing of horses and other livestock, this being an attempt, sometimes successful, to change his intended victim from horseman to foot soldier.

“When the Chichimeca was attacked in his mountainous or other naturally protected stronghold or hideout, he usually put up vigorous resistance, especially if unable to escape onslaught. In such cases he fought — with arrows, clubs, or even rocks — behind natural barriers (or in caves) that had sometimes been made stronger by his own hands and ingenuity. Even the women might take up the fight, using the weapons of fallen braves….

The high degree of Chichimeca accuracy with bow and arrow called forth much respectful and awed comment from his Spanish enemy. ‘On one occasion I saw them throw an orange into the air, and they shot into it so many arrows that, having held it in the air for much time, it finally fell in minute pieces.’ ‘In the opinion of men experienced in foreign lands, the [Zacatecanos] are the best archers in the world.’ ‘They kill hares which, even though running, they pierce with arrows; also deer, birds, and other little animals of the land, not even overlooking rats … and they fish with the bow and arrow.’ Children of the Chichimecas were taught the use of the bow from the time they could walk, and they practiced by shooting at insects and the smallest animals.

The forces and penetrating power of the Chichimeca arrow was always a puzzle to Spaniards, particularly in view of the extreme thinness of the arrow shaft. ‘It has happened that, in a fight between some soldiers, and some Chichimeca Indians, an arrow hit one soldier’s powder flask [of wood, usually], passed completely through it, then penetrated his armor, consisting of eleven thicknesses of buckskin (*gamuza*), a coat of mail, a doublet, and the soldier was wounded by said arrow.’ ‘It has happened that an arrow hit a horse on which a soldier was fighting and the arrow passed through the horse’s crownpiece (which consisted of a very strong leather and metal piece), his head, and came out through the neck and entered the chest, a thing which, if were not known to be certain, seems incredible.’ ‘One of don Alonso de Castilla’s soldiers had an arrow pass through the head of his horse, including a crownpiece of doubled buckskin and metal, and into his chest, so he fell with the horse dead on the ground — this was seen by many who are still living.’

The Chichimeca bow was about two-thirds as long as the average body, reaching approximately from head to knee; it was probably made of such materials as cottonwood, willow, mesquite, *bois d’arc*, or juniper — woods that could be found in the area. The arrow, about two-thirds as long as the bow, was very thin, usually made of reed and usually with an obsidian tip, which was fastened to the shaft by human sinews or animal tendons. Shortness of bow, thinness of arrow, and the conchoidal edge of the obsidian combined to achieve a penetration the Spaniards could hardly believe. The fact that the Chichimeca arrow found its way through all but the closest-woven mail was a factor in the increasing Spanish use of buckskin armor on this frontier.

There are apparently more Zacatecanos in the US than in their native state in Mexico.

Algebra and the Pointlessness of The Whole Damn Thing

Wednesday, August 7th, 2013

Is algebra necessary? The education realist recaps the major points of view:

Hacker:

We shouldn’t make everyone take algebra. No one needs algebra anyway; we never really use it. Statistics would be much more useful. Algebra is the primary obstacle to high school success; millions of kids are failing because they can’t manage this course. If we just allowed students to have an easier time in high school, more of them would graduate successfully and go on to college.

Outraged Opposition:

Algebra is essential to college success and “real life” and one of many obstacles to high school success. No one is happy with the current state of affairs, but it’s clear that kids aren’t learning algebra because their teachers suck, particularly in elementary school. We need to teach math better in the lower grades, rather than lower our standards. Besides, the corollary to “not everyone should take algebra” is “some people should take algebra” and just how are you planning to divide up those teams? (Examples: Dan Willingham, Dropout Nation)

Judicious Analysis:

Sigh. Guys, this is really a debate about tracking, you know? And no one wants to go there. While it’s true that algebra really isn’t necessary for college, colleges use success in advanced math as a convenient sorting mechanism. Besides, once we say algebra isn’t necessary, where do we stop? Literature? Biology? Chemistry? But without doubt, Hacker is right in part. Did I say that no one wants to go there? Or just hint it really, really loudly?

Examples: Dana Goldstein, Justin Baeder Iand II.

Voldemort Support:

Well, of course not everyone should take algebra, trig, or calculus. Or advanced literature. Or science. Not everyone has the cognitive ability or the interest. We should have a richer and more flexible curriculum, allowing anyone with the interest to take whatever classes they like with the understanding that not all choices lead to college and that outcomes probably won’t have the racial distributions we’d all prefer to see. Oh, and while we’re at it, we should be reviewing our immigration policies because it’s pretty clear that our country doesn’t need cheap labor right now.

Hacker, Outraged Opposition and Judicious Analysis to Voldemort Support:

Shut up, racist!

Under the Knife

Tuesday, August 6th, 2013

I recently mentioned how anesthesia spread rapidly, but antisepsis did not, and Civil War field surgery exemplifies this:

Civil War surgeons almost always had chloroform to anesthetize patients before an amputation. The chloroform was dripped onto a piece of cloth held over the patient’s face until he was unconscious. Although not an exact science, the procedure worked well, and few patients died from overdose. Opium pills, opium dust and injections were also available to control postoperative pain.

The mistaken belief that amputations were routinely performed without anesthetics can be partially attributed to the fact that chloroform did not put patients into a deep unconscious state. Bystanders who saw moaning, writhing patients being held down on the table assumed no anesthetic was being used. As in the case of General Ewell, patients often reacted to the scalpel and bone saw as if in pain, but they did not remember it afterward. After his left arm was amputated (Dr. McGuire also performed that operation), Stonewall Jackson mentioned that he had heard the most beautiful music while under the chloroform. Upon reflection, he said, “I believe it was the sawing of the bone.”

[...]

Early in the war surgeons earned the nickname “Saw-bones” because they seemed eager to amputate. This eagerness stemmed not from overzealousness but from the knowledge that infections developed quickly in mangled flesh, and amputation was the most effective way to prevent it. Those limbs removed within 48 hours of injury were called primary amputations, and those removed after 48 hours were called secondary amputations. The mortality rate for primary amputations was about 25 percent; that for secondary amputations was twice as high, thanks to the fact that most secondary amputations were performed after gangrene or blood poisoning developed in the wound. Surgeons learned that amputating the limb after it became infected actually caused the infection to spread, and patients frequently died. Thus, the patient was much more likely to survive if a primary amputation was performed before infection set in.

[...]

Nonetheless, it is estimated that approximately three out of four soldiers survived amputations. Amazingly, some, like Confederate Brig. Gen. Francis T. Nicholls, endured more than one. His lower left arm was amputated after he was shot at the First Battle of Winchester and his left foot was taken off when he was wounded at Chancellorsville. After the war, Nicholls was a popular Louisiana governor who was said to ask people to vote for “all that’s left of General Nicholls” and to support him for governor because he was “too one sided to be a judge.”

Often, surviving an amputation seemed to be completely random. While some, like Ewell and Nicholls, seemed unhindered by the surgery, others died from what appeared to be rather minor wounds. Two members of Company B, 19th Michigan Infantry, were shot in the index finger in the same battle during the Atlanta campaign. One man treated himself by cutting off the mangled finger with his pocket knife. He wrapped the stub in a handkerchief and waited until the battle was over to have the wound dressed at the field hospital. The other soldier went immediately to the surgeon for a proper amputation. Gangrene set in within days, and the surgeon was later forced to amputate his arm at the shoulder. The soldier died soon afterward. The man who treated himself made a full recovery and lived to a ripe old age.

(Hat tip to Weapons Man.)

Most Americans Against Race-Based College Admissions

Tuesday, August 6th, 2013

According to a recent Gallup poll most Americans are against race-based college admissions:

Two-thirds of Americans believe college applicants should be admitted solely based on merit, even if that results in few minorities being admitted, while 28% believe an applicant’s racial and ethnic background should be taken into account to promote diversity on college campuses.

Since we live in a democracy, I’m sure race-based college admissions will soon end. It’s the will of the People.

Curare

Tuesday, August 6th, 2013

The Yanomamö have curare, the infamous poison, but it’s a very poor form of curare:

There are a lot of tribes in the Amazon Basin that can make really lethal curare. If you scratch yourself, uh, frog poison. I mean a certain kind of frog exudes a very toxic substance that’s lethal. Anyway, the Yanomamö have a really crude way of making curare. Curare is a mixture of the curare and a bunch of other stuff, I don’t know what the other stuff does. They say it adds adhesive qualities to it. It makes it sticky, and sticks to the arrow point. They put a whole bunch of pencil-length pieces of palm wood, and it’s hard as a rock, the palm wood is, and they weaken it by cutting it every inch or so. So when it hits something, it breaks off, and they put poison on it. And when they shoot a monkey, for example, the monkey gets pierced with the curare tipped arrow, it breaks off and leaves the point inside of the monkey, and the monkey just eventually relaxes. The curare relaxes muscles.

Hagwon

Monday, August 5th, 2013

Kim Ki-hoon earns $4 million a year as a teacher in South Korea — at a private after-school tutoring academy, or hagwon:

Mr. Kim works about 60 hours a week teaching English, although he spends only three of those hours giving lectures. His classes are recorded on video, and the Internet has turned them into commodities, available for purchase online at the rate of $4 an hour. He spends most of his week responding to students’ online requests for help, developing lesson plans and writing accompanying textbooks and workbooks (some 200 to date).

South Korea has dramatically improved its education system over the past several decades:

Sixty years ago, most South Koreans were illiterate; today, South Korean 15-year-olds rank No. 2 in the world in reading, behind Shanghai. The country now has a 93% high-school graduation rate, compared with 77% in the U.S.

Of course, we might ask what the numbers look like for Korean-Americans.

Anyway, these private cram schools — as we called them back when these stories were about Japan — are big business:

Nearly three of every four South Korean kids participate in the private market. In 2012, their parents spent more than $17 billion on these services. That is more than the $15 billion spent by Americans on videogames that year, according to the NPD Group, a research firm. The South Korean education market is so profitable that it attracts investments from firms like Goldman Sachs, the Carlyle Group and A.I.G.

Students sign up for specific teachers, so “better” teachers get more students and make more money:

Performance evaluations are typically based on how many students sign up for their classes, their students’ test-score growth and satisfaction surveys given to students and parents. “How passionate is the teacher?” asks one hagwon’s student survey—the results of which determine 60% of the instructor’s evaluation. “How well-prepared is the teacher?” (In 2010, researchers funded by the Bill & Melinda Gates Foundation found classroom-level surveys like this to be surprisingly reliable and predictive of effective teaching in the U.S., yet the vast majority of our schools still don’t use them.)

[...]

All of this pressure creates real incentives for teachers, at least according to the kids. In a 2010 survey of 6,600 students at 116 high schools conducted by the Korean Educational Development Institute, Korean teenagers gave their hagwon teachers higher scores across the board than their regular schoolteachers: Hagwon teachers were better prepared, more devoted to teaching and more respectful of students’ opinions, the teenagers said. Interestingly, the hagwon teachers rated best of all when it came to treating all students fairly, regardless of the students’ academic performance.

Private tutors are also more likely to experiment with new technology and nontraditional forms of teaching.

Donating Kaizen

Monday, August 5th, 2013

Instead of a check, Toyota offered New York City’s Food Bank kaizen — even though the charity wanted money more than expertise:

Toyota’s initial offer to the charity in 2011 was met with apprehension.

“They make cars; I run a kitchen,” said Daryl Foriest, director of distribution at the Food Bank’s pantry and soup kitchen in Harlem. “This won’t work.”

When Toyota insisted it would, Mr. Foriest presented the company with a challenge.

“The line of people waiting to eat is too long,” Mr. Foriest said. “Make the line shorter.”

Toyota’s engineers went to work. The kitchen, which can seat 50 people, typically opened for dinner at 4 p.m., and when all the chairs were filled, a line would form outside. Mr. Foriest would wait for enough space to open up to allow 10 people in. The average wait time could be up to an hour and a half.

Toyota made three changes. They eliminated the 10-at-a-time system, allowing diners to flow in one by one as soon as a chair was free. Next, a waiting area was set up inside where people lined up closer to where they would pick up food trays. Finally, an employee was assigned the sole duty of spotting empty seats so they could be filled quickly. The average wait time dropped to 18 minutes and more people were fed.

(Hat tip to Kevin Meyer.)

Matches and Aluminum Pots

Monday, August 5th, 2013

When Napoleon Chagnon first arrived, the Yanomamö would make fire with a fire drill:

And when I was there for the first year of my field work life, maybe two years, every Yanomamö man had a little bamboo carrying case, a section of bamboo that’s hollow, and it would have extra arrow points, because if you shoot a certain kind of arrow it breaks every time, so you have to replace it, and you have to carry spares. And strapped to that bamboo point carrying case, the quiver, which is a piece of cord around the neck, there was always a chunk of soft wood that was cylindrical, with evidence that it had been used to light a fire, and they would, I mean that was their matches. And they could do it fairly quickly. When matches were introduced, those disappeared.

And when aluminum pots were introduced, their pottery disappeared. They made a pot that was about that high, narrow at the bottom, and it flared up on the sides, and they were so crudely fired that if they’d fall over they’d smash. So they carried them in pack baskets. They made these big baskets that the women harvested their produce in, bananas. When they moved from one place to another, they’d carefully pack this crudely fired clay pot in the basket, and then surround it with vine hammocks so it wouldn’t wiggle. And they took very good care of those.  When aluminum pans came in, they just stopped doing it. And for a while you could find chunks of the clay pots being used in their drug-taking, because the clay pot is a much nicer surface to grind their drugs on than an aluminum cooking pot.

Measurement Inversion

Sunday, August 4th, 2013

In his review of How to Measure Anything, Luke Muehlhauser cites this passage about measurement inversion:

By 1999, I had completed the… Applied Information Economics analysis on about 20 major [IT] investments… Each of these business cases had 40 to 80 variables, such as initial development costs, adoption rate, productivity improvement, revenue growth, and so on. For each of these business cases, I ran a macro in Excel that computed the information value for each variable… [and] I began to see this pattern:

  • The vast majority of variables had an information value of zero…
  • The variables that had high information values were routinely those that the client had never measured…
  • The variables that clients [spent] the most time measuring were usually those with a very low (even zero) information value…

Since then, I’ve applied this same test to another 40 projects, and… [I’ve] noticed the same phenomena arise in projects relating to research and development, military logistics, the environment, venture capital, and facilities expansion.

In Robin Hanson’s experience trying to sell prediction markets to firms, they usually express strong reluctance and even hostility to making markets on the specific topics that seem to be of the most info value:

They choose instead to estimate safer safer things, less likely to disrupt the organization.

For example, the most dramatic successes of prediction markets, i.e., where correct market forecasts most differ from official forecasts, are for project deadlines. Yet even hearing this few orgs are interested in starting such markets, and those that do and see dramatic success usually shut them down, and don’t do them again. One plausible explanation is that project managers want the option to say after a failed project “no one could have known about those problems.” Prediction markets instead create a clear record that people did in fact know.

If you’re not familiar with the book, Aretae recommends it highly — and summarizes what he learned:

  1. Measurement doesn’t quite mean what you think it means, and what it does mean is really important.
  2. Measures (and estimates) are always ranges + probabilities. They are not just numbers.
  3. If you ask someone to give you a 90% range, they will be wrong (on the too narrow side). You have to practice to get these ranges right.
  4. People mostly measure stuff they don’t need to measure at high cost, and don’t measure the important stuff at all.
  5. For anything you would like to measure, you can…it’s not too hard.
  6. Statistics + Excel can give you the rest of the information you need, both about what to measure and what the results mean.

Infanticide and Abortion

Sunday, August 4th, 2013

The Yanomamö practice infanticide — like many societies:

Dennett: Would you imagine discovering a behavior, a practice, a policy in a tribe that was so repugnant to Western sensibilities that you would decide not to write about that?

Chagnon: Well, the Yanomamö practice infanticide occasionally, and it’s for a variety of reasons. One of them being if they suspect that the newborn infant is deformed, and it can be traced right back to parental investment. Why invest in a losing prospect? Let’s terminate the infant now and start anew. Another example of infanticide is, this is even rarer, that some guy was cuckolded by, or suspected he was cuckolded by some other guy, and he puts pressure on his wife to kill the new infant. That’s not very common, but I’ve heard of it. And I began reporting, as soon as I learned this, that the Yanomamö practice infanticide, and I didn’t make a big case out of it. When I learned that a deputado in the Venezuelan government — which is basically like a representative or a senator — had learned that there were people in her country that were killing their own children, she wanted to go in and arrest these people and put them in jail. So I stopped reporting any information I acquired about Yanomamö infanticide, not because it was disgusting to Westerners, because I’ll bet if you looked at the abortion rate in Venezuela in middle class women, their rate of abortion would be much, much higher than the Yanomamö infanticide.

Pinker: Well, in fact, historically, I’ve seen an estimate — it averages over many peoples, and there’s a lot of variation underneath it — that the traditional infanticide rate was about 15 percent of live births, which is pretty close to the …

Chagnon: In Western culture?

Pinker: No No, in non-Western cultures. Which is pretty close to the abortion rate in the West, until recently.

Chagnon: Oh, really?

Pinker: The abortion rate has since then come down. But there is something to the idea that abortion in the West serves a similar purpose to infanticide in traditional cultures.

Chagnon: That’s right. It’s a definitional matter, so don’t get uptight about Yanomamö practicing infanticide when your sister or your wife has had an abortion. I mean if you want to make a moral issue out of it, let’s include everybody.

Policia

Saturday, August 3rd, 2013

The Yanomamö often find themselves caught in a cycle of violence, where each revenge killing demands another. Do they ever see the futility of their situation?

And the answer to that is best explicated in an incident that happened to me when the Yanomamö began being aware of Venezuelans, for example. It was a territorial capital 200+ miles away, and some of the missionaries sent young guys to the territorial capital to learn practical nursing to come back to the village and treat snake bites, and scratches, and wounds, and things like that, and to give them malaria pills. And they taught them how to use microscopes.

But one of these guys came back and he was just terribly excited when he told me that he discovered policia. I was like, “Well, what’s policia?” “They will grab people and haul them off and put them in these little separate houses, if they do something wrong. And I think we need policia, because my brother killed a man from Iwahikorobateri five years ago, and I’m always worried that the Iwahikorobateri are going to come and kill me, because he’s my brother.” And he thought that if they had law, law would be a good thing.

And ironically, the whole origin of anthropology began when early lawyers were astonished when they came to the New World and saw all of these huge populations living in harmony, and they couldn’t understand how they could do it. Well, kinship was part of the answer. But they began thinking seriously. Well, it goes back to Plato, too, about the origin of the state. But a lot of legal minds — in England and in the United States — were astonished that the political state could evolve out of primitive tribes like the American Indians.

How to Lose a War

Friday, August 2nd, 2013

We have many books and papers outlining how to win wars — including classics, such as Sun Tzu’s The Art of War, Thucydides’ The History of the Peloponnesian War, and Clausewitz’s On War — but we may get more mileage out of a primer on how to lose a war, Zen Pundit suggests:

  1. War is the Continuation of Domestic Politics
  2. Policy is the True Fog of War
  3. Strategy is a Constraint to be Avoided
  4. All Lost Wars are based on Self-Deception
  5. Isolate the War and those Fighting it from the People
  6. Complexity = Opacity and Micromanagement = Power
  7. Enormous Tail, Tiny Tooth: the Worse the ROI the Better
  8. Cultivate Hatred and Contempt
  9. Protect that Which is Most Unimportant
  10. Level the Playing Field: Paralyze Your Own Tactical Advantages

King’s Table

Friday, August 2nd, 2013

Hnefatafl, or King’s Table, was the chess, the checkers, the go, and the Nintendo of the Norse during the Viking Age:

Today, only dedicated tabletop gamers have ever heard of it and many of them have never had a chance to play the game. That is a shame for it’s an extraordinary game with a number of lessons embedded in it for the curious intelligence professional. For example:

  • It is an asymmetric game. As you can see from the board above, one side starts in the center and the other side surrounds it on all four sides. One side outnumbers the other by about 2:1. The sides even have different victory conditions (the player with the pieces in the center need to get the “King”, the large playing piece in the middle of the board, to one of the corners. The other player is trying to capture the King). It is not too hard to see a game such as this one incorporated into courses, classes or discussions of asymmetric warfare.
  • It is a conflict simulation. Most historians agree that there were relatively few large scale battles involving Vikings. Instead, most of the time, combat resulted from raiding activities. Hnefatafl seems to reflect the worst case scenario for a Viking raider: Cut off from your boats and outnumbered 2:1.
  • It provides a deep lesson in strategic thinking. Lessons in both the strategy of the central position (hundred of years before Napoleon made it famous) and in the relative value of interior vs. exterior lines of communication are embedded in this game.

What makes this game even more fascinating for me is what it teaches implicitly — that is, what are the lessons it teaches the players without the players knowing that they are learning?

Hnefatafl or King's Table

Furthermore, what does this tell us about the Viking culture? For example:

  • It takes two soldiers to kill another soldier. This is one of the few games where it takes more than one piece to capture another piece. Basically, one pins and the other piece comes up and deals the killing blow.
  • It is good to be King. The only piece that really matters is the King. If the King escapes and loses 90% of his soldiers in the process, it is still a victory. Likewise, if the King is captured but at a horrific cost to the enemy, it is still a loss.
  • It is easier for the player in the center to win. You heard that right, because of the value of interior lines and because of the difficulty of capturing the King, the player who is surrounded, cut-off and outnumbered 2:1 has the advantage. In fact, in games with novices a simple, “fight through the ambush” strategy almost always wins.

Now, imagine this game being played night after night in the langhus of some Viking Jarl. What lessons are being implicitly conveyed to the young Viking warriors? Work together, protect the King, and don’t worry about how bad it looks — we can win! All in all, not a bad way to teach important lessons in a barely literate society.

The Yanomamö Conundrum

Friday, August 2nd, 2013

The Yanomamö — the fierce people — don’t like to fight actually, Napoleon Chagnon says:

They prefer to be friendly, amicable, and live life in harmony. But they’re caught in a conundrum of the following sort. The only way you can live that nice happy free life is if you’re in a small community, like 25 people, most of whom are children. So everything is happy and friendly. People get along with each other. But a village of 25 people is extremely vulnerable to raids from the outside, and the men will come in and steal the women, and send the men packing, or shoot the men and take the women. So they’re constantly being pressured to maximize the size of their village. And as you increase the number of people in the village, you get increasing amounts of conflict.

[...]

And occasionally they’ll explain to me, I mean the question I always ask in all villages, why did such and such a group fission away from such and such a group? And occasionally they’ll say, “We’ve just got so damn many people that we’re on each other’s nerves all the time, so we just split apart.” But when the intensity of warfare is high, it would be really hazardous to split apart. And what I often found is, you know, the garden that might be 20 acres large, this is a big garden, and a fight might occur in the village that might be 200 people, and instead of picking up and moving the next valley over, they can’t, because they’re too dependent on their gardens. So they split the group into two parts, each locating in a different part of the garden. Then they begin transplanting their plantain cuttings, their banana cuttings, and tubers to some other location, maybe a day’s walk away, until they get that garden developed to the point that it can feed them. Then they move away. But they may rejoin and move away again.

[...]

Big villages lord over small villages. So if you’re seeking an ally who will protect you from the people up the hill who are bigger than you, you’re at a disadvantage because in order to get allies, you’ve got to give women to them. It’s an economics game where the smaller village has to pay up front for the privileges of the alliance, and the bigger village tends to default on many of its agreements. So big villages tend to exploit small villages. It’s always a good idea to live in a big village; however, it’s like living in a powder keg.

Pushing microscopy beyond standard limits

Thursday, August 1st, 2013

Engineers at the California Institute of Technology (Caltech) are pushing microscopy beyond standard limits:

“One big advantage of this new approach is the hardware compatibility,” Zheng says, “You only need to add an LED array to an existing microscope. No other hardware modification is needed. The rest of the job is done by the computer.”

The new system acquires about 150 low-resolution images of a sample. Each image corresponds to one LED element in the LED array. Therefore, in the various images, light coming from known different directions illuminates the sample. A novel computational approach, termed Fourier ptychographic microscopy (FPM), is then used to stitch together these low-resolution images to form the high-resolution intensity and phase information of the sample — a much more complete picture of the entire light field of the sample.

FPM Microscope

Yang explains that when we look at light from an object, we are only able to sense variations in intensity. But light varies in terms of both its intensity and its phase, which is related to the angle at which light is traveling.

“What this project has developed is a means of taking low-resolution images and managing to tease out both the intensity and the phase of the light field of the target sample,” Yang says. “Using that information, you can actually correct for optical aberration issues that otherwise confound your ability to resolve objects well.”

The very large field of view that the new system can image could be particularly useful for digital pathology applications, where the typical process of using a microscope to scan the entirety of a sample can take tens of minutes. Using FPM, a microscope does not need to scan over the various parts of a sample — the whole thing can be imaged all at once. Furthermore, because the system acquires a complete set of data about the light field, it can computationally correct errors — such as out-of-focus images — so samples do not need to be rescanned.