Sugar not Salt

Friday, September 19th, 2014

It is sugar, not salt, that causes high blood pressure, according to a new paper published in the American Journal of Cardiology:

‘This notion is supported by meta analyses of randomised control trials (large-scale studies) suggesting that sugar is more strongly related to blood pressure in humans than sodium.

‘Encouraging consumers to hold the sugar, not the salt, may be the better dietary strategy to achieve blood pressure control.’

Back in 1986, Linus Pauling cited John Yudkin‘s work, in How to Live Longer and Feel Better:

Against the general public acceptance of the proposition that coronary heart disease is caused by a high intake of animal fat (saturated fat) and the eating of foods containing cholesterol, Yudkin himself has shown that for some countries the correlation of coronary disease with intake of sugar is much better than that with intake of fat.

(Hat tip to Mangan.)

Tarot Counselors

Tuesday, September 16th, 2014

Robin Hanson recently watched a demonstration of Tarot card reading:

The reader threw out various associations of the cards she threw down, and watched the subject carefully for reactions, moving the interpretation closer to the options in which the client seemed to be more engaged. Though the subject was a skeptic, she admitted to finding the experience quite compelling.

Contrast such life readings to school career counselors. Such counselors usually refer to statistics about the income or gradations rates of broad categories of people given certain types of careers, colleges, or majors. Such advice may be evidence based but it seems far less compelling to students. It is not connected to salient recent personal experiences or the subjects, or to outcomes in which they are very emotionally engaged. It is clear but uncertain, in contrast to the certainty and ambiguity of Tarot readings.

It seems obvious to me that many students would be more engaged by more Tarot like career counseling. It also seems obvious that many parents and other citizens would loudly object, as this would be seen as unscientific and lower the status of this school, at least among elites. Even if the process just took on the appearance of Tarot readings but mainly gave the usual career counseling content.

The high status of science seems to push many people to have less compelling and engaging stories of their lives, even if such stories are more accurate.

How Caffeine Evolved to Help Plants Survive

Tuesday, September 16th, 2014

The ability to produce caffeine evolved separately in multiple different plants:

When coffee leaves die and fall to the ground, they contaminate the soil with caffeine, which makes it difficult for other plants to germinate. Coffee may thus use caffeine to kill off the competition.

Coffee plants also use caffeine to ward off insects that would otherwise feast on their leaves and beans. At high doses, caffeine can be toxic to insects. As a result, insects have evolved taste receptors that help them avoid ingesting caffeine.

But coffee and a number of other plants also lace their nectar with low doses of caffeine, and in that form, it seems to benefit the plants in a different way.

Plants make nectar to feed insects and other animals so they’ll spread their pollen. When insects feed on caffeine-spiked nectar, they get a beneficial buzz: they become much more likely to remember the scent of the flower. This enhanced memory may make it more likely that the insect will revisit the flower and spread its pollen further.

Salt Doesn’t Cause High Blood Pressure

Friday, September 12th, 2014

A new study published in the American Journal of Hypertension analyzed data from 8,670 French adults and found that salt consumption wasn’t associated with systolic blood pressure in either men or women after controlling for factors like age:

It should be noted, however, that even though the study found no statistically significant association between blood pressure and sodium in the diet, those patients who were hypertensive consumed significantly more salt than those without hypertension — suggesting, as other research has, that salt affects people differently.

As for the factors that did seem to influence blood pressure, alcohol consumption, age, and most of all BMI were strongly linked to a rise. Eating more fruits and vegetables was significantly linked to a drop.

Euharamiyida

Thursday, September 11th, 2014

New specimens place three species of Euharamiyida firmly within the class of Mammals — a long, long time ago:

Paleontologists have described three new small squirrel-like species that place a poorly understood Mesozoic group of animals firmly in the mammal family tree. The study, led by scientists at the American Museum of Natural History and the Chinese Academy of Sciences, supports the idea that mammals — an extremely diverse group that includes egg-laying monotremes such as the platypus, marsupials such as the opossum, and placentals like humans and whales — originated at least 208 million years ago in the late Triassic, much earlier than some previous research suggests.

The study is published today in the journal Nature.

“For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” said co-author Jin Meng, a curator in the Museum’s Division of Paleontology. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

The three new species — Shenshou lui, Xianshou linglong, and Xianshou songae — are described from six nearly complete 160-million-year-old fossils found in China. The animals, which researchers have placed in a new group, or clade, called Euharamiyida, likely looked similar to small squirrels. They weighed between 1 and 10 ounces and had tails and feet that indicate that they were tree dwellers.

Arboreal Mammals in a Jurassic Forest

“They were good climbers and probably spent more time than squirrels in trees,” Meng said. “Their hands and feet were adapted for holding branches, but not good for running on the ground.”

The members of Euharamiyida likely ate insects, nuts, and fruit with their “strange” teeth, which have many cusps, or raised points, on the crowns. Mammals are thought to evolve from a common ancestor that had three cusps; human molars can have up to five. But the newly discovered species had two parallel rows of cusps on each molar, with up to seven cusps on each side. How this complex tooth pattern evolved in relation to those of other mammals has puzzled scientist for many decades.

Despite unusual tooth patterning, the overall morphology, or physical characteristics, seen in the new haramiyidan fossils is mammalian. For example, the specimens show evidence of a typical mammalian middle ear, the area just inside the eardrum that turns vibrations in the air into ripples in the ear’s fluids. The middle ears of mammals are unique in that they have three bones, as evidenced in the new fossils.

However, the placement of the new species within Mammalia poses another issue: Based on the age of the Euharamiyida species and their kin, the divergence of mammals from reptiles had to have happened much earlier than some research has estimated. Instead of originating in the middle Jurassic (between 176 and 161 million years ago), mammals likely first appeared in the late Triassic (between 235 and 201 million years ago). This finding corresponds with some studies that used DNA data.

“What we’re showing here is very convincing that these animals are mammals, and that we need to turn back the clock for mammal divergence,” Meng said. “But even more importantly, these new fossils present a new suite of characters that might help us tell many more stories about ancient mammals.”

Society Is Fixed, Biology Is Mutable

Thursday, September 11th, 2014

While sitting through a lecture on ADHD, Scott Alexander realized that he rejected a popular premise:

There’s this stereotype that the Left believes that human characteristics are socially determined, and therefore mutable. And social problems are easy to fix, through things like education and social services and public awareness campaigns and “calling people out”, and so we have a responsiblity to fix them, thus radically improving society and making life better for everyone.

But the Right (by now I guess the far right) believes human characteristics are biologically determined, and biology is fixed. Therefore we shouldn’t bother trying to improve things, and any attempt is just utopianism or “immanentizing the eschaton” or a shady justification for tyranny and busybodyness.

And I think I reject this whole premise.

See, my terrible lecture on ADHD suggested several reasons for the increasing prevalence of the disease. Of these I remember two: the spiritual desert of modern adolescence, and insufficient iron in the diet. And I remember thinking “Man, I hope it’s the iron one, because that seems a lot easier to fix.”

Society is really hard to change. We figured drug use was “just” a social problem, and it’s obvious how to solve social problems, so we gave kids nice little lessons in school about how you should Just Say No. There were advertisements in sports and video games about how Winners Don’t Do Drugs. And just in case that didn’t work, the cherry on the social engineering sundae was putting all the drug users in jail, where they would have a lot of time to think about what they’d done and be so moved by the prospect of further punishment that they would come clean.

And that is why, even to this day, nobody uses drugs.

On the other hand, biology is gratifyingly easy to change. Sometimes it’s just giving people more iron supplements.

How Scientists See the World

Friday, September 5th, 2014

This is how scientists see the world, according to Abstruse Goose:

Abstruse Goose All I see are equations

(Hat tip to Candide III.)

Fruits and Vegetables Are Trying to Kill You

Thursday, September 4th, 2014

Vegetable KnightFruits and vegetables are trying to kill you — and that only makes you stronger:

That stress comes courtesy of trace amounts of naturally occurring pesticides and anti-grazing compounds. You already know these substances as the hot flavors in spices, the mouth-puckering tannins in wines, or the stink of Brussels sprouts. They are the antibacterials, antifungals, and grazing deterrents of the plant world. In the right amount, these slightly noxious substances, which help plants survive, may leave you stronger.

[...]

The nicotine that we so prize in tobacco slows grazing insects. Beans contain lectins, which defend against insects. Garlic’s umami-like flavor comes from allicin, a powerful antifungal. These “antifeedants” have evolved in part to dissuade would-be grazers, like us.

Mattson and his colleagues say these plant “biopesticides” work on us like hormetic stressors. Our bodies recognize them as slightly toxic, and we respond with an ancient detoxification process aimed at breaking them down and flushing them out.

Consider fresh broccoli sprouts. Like other cruciferous vegetables, they contain an antifeedant called sulforaphane. Because sulforaphane is a mild oxidant, we should, according to old ideas about the dangers of oxidants, avoid its consumption. Yet studies have shown that eating vegetables with sulforaphane reduces oxidative stress.

When sulforaphane enters your blood stream, it triggers release in your cells of a protein called Nrf2. This protein, called by some the “master regulator” of aging, then activates over 200 genes. They include genes that produce antioxidants, enzymes to metabolize toxins, proteins to flush out heavy metals, and factors that enhance tumor suppression, among other important health-promoting functions.

In theory, after encountering this humble antifeedant in your dinner, your body ends up better prepared for encounters with toxins, pro-oxidants from both outside and within your body, immune insults, and other challenges that might otherwise cause harm. By “massaging” your genome just so, sulforaphane may increase your resistance to disease.

In a study on Type 2 diabetics, broccoli-sprout powder lowered triglyceride levels. High triglycerides, a lipid, are associated with an increased risk of heart disease and stroke. Lowering abnormally elevated triglycerides may lessen the risk of these disorders. In another intervention, consuming broccoli sprout powder reduced oxidative stress in volunteers’ upper airways, likely by increasing production of native antioxidants. In theory, that might ameliorate asthmatics’ symptoms.

Elevated free radicals and oxidative stress are routinely observed in diseases like cancer and dementia. And in these instances, they probably contribute to degeneration. But they may not be the root cause of disease. According to Mattson, the primary dysfunction may have occurred earlier with, say, a creeping inability to produce native antioxidants when needed, and a lack of cellular conditioning generally.

Mattson calls this the “couch potato” problem. Absent regular hormetic stresses, including exercise and stimulation by plant antifeedants, “cells become complacent,” he says. “Their intrinsic defenses are down-regulated.” Metabolism works less efficiently. Insulin resistance sets in. We become less able to manage pro-oxidant threats. Nothing works as well as it could. And this mounting dysfunction increases the risk for a degenerative disease.

Implicit in the research is a new indictment of the Western diet. Not only do highly refined foods present tremendous caloric excess, they lack these salutary signals from the plant world—“signals that challenge,” Mattson says. Those signals might otherwise condition our cells in a way that prevents disease.

Another variant of the hormetic idea holds that our ability to receive signals from plants isn’t reactive and defensive but, in fact, proactive. We’re not protecting ourselves from biopesticides so much as sensing plants’ stress levels in our food.

Harvard scientist David Sinclair and his colleague Konrad Howitz call this xenohormesis: benefitting from the stress of others. Many phytonutrients trigger the same few cellular responses linked to longevity in eukaryotic organisms, from yeasts to humans. Years of research on Nrf2 in rodents suggest that activating this protein increases expression of hundreds of health-promoting genes, including those involved in detoxification, antioxidant production, control of inflammation, and tumor suppression.”

People Faster to Shoot White Suspects than Black Suspects

Wednesday, September 3rd, 2014

People are faster to shoot white suspects than black, a new study has found:

When confronted by an armed white person, participants took an average of 1.37 seconds to fire back. Confronted by an armed black person, they took 1.61 seconds to fire and were less likely to fire in error. The 24-millisecond difference may seem small, but it’s enough to be fatal in a shooting.

[...]

This behavioral ‘counter-bias’ might be rooted in people’s concerns about the social and legal consequences of shooting a member of a historically oppressed racial or ethnic group.

Shrinking Tumors with Bacteria

Wednesday, September 3rd, 2014

In the 1890s, cancer researcher William Coley noticed that some patients who developed postsurgical infections went into remission. Now scientists have shown that injections of a weakened bacterium — Clostridium novyi — can shrink tumors in rats and pet dogs:

The advantage of using Clostridium novyi is that it thrives only in oxygen-poor environments, such as those prevailing deep within tumors. These troublesome spots lack the blood and oxygen needed for traditional therapies to work. But where chemotherapy and radiation struggle to have an effect, hypoxia-tolerant microbes may mount an infection and induce a strong immune response. Even better, the microbes may stop when they reach healthy tissue.

In their study, the researchers introduced several innovations: They removed one of the Clostridium novyi bacterium’s toxin-producing genes to make C. novyi-NT, which is safer for therapeutic use. They elected to inject bacterial spores directly into tumors rather than rely on the intravenous route. (In earlier studies, few bacterial spores that had been injected into experimental animals actually reached tumors.) Finally, they expanded their investigation beyond rats.

“It is well known that experimental models often do not reliably predict the responses of human patients to therapeutic agents,” wrote the authors. “We therefore used naturally occurring canine tumors as a translational bridge to human trials. Canine tumors are more like those of humans because they occur in animals with heterogeneous genetic backgrounds, are of host origin, and are due to spontaneous rather than engineered mutations.”

The researchers tested direct-tumor injection of the C. noyvi-NT spores in 16 pet dogs that were being treated for naturally occurring tumors. Six of the dogs had an antitumor response 21 days after their first treatment. Three of the six showed complete eradication of their tumors, and the length of the longest diameter of the tumor shrunk by at least 30% in the three other dogs. Most of the dogs experienced side effects typical of a bacterial infection, such as fever and tumor abscesses and inflammation.

“On the basis of these encouraging results, we treated a human patient who had an advanced leiomyosarcoma with an intratumoral injection of C. novyi-NT spores,” the researchers continued. “This treatment reduced the tumor within and surrounding the bone.”

Studies in other patients are currently underway at multiple sites to test the safety and efficacy of this new approach.

The Brachistochrone Challenge

Saturday, August 30th, 2014

If you want to roll a ball down a slope, what shape of slope will get the ball from point A to point B in the least time? This is the so-called brachistochrone challenge.

At first you might naively assume that a straight line would get the ball to its destination in the least time, because the shortest distance between two point is a straight line, but the ball is not moving at a constant speed.

In fact, because it needs to get rolling, the ball will travel down a concave ramp much faster than down a convex ramp. But which concave curve?

Brachistochrone Challenge

The winning curve is an inverted cycloid, the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line.

Cycloid

(Hat tip to Charles.)

Flatley’s Law

Friday, August 29th, 2014

Over the past 13 years, the cost of sequencing DNA has dropped from $100 million per human genome to only $1,000:

The only thing more extraordinary than the growth rate of the sequencing revolution is that the beneficiary is a single company, Illumina of San Diego, and most of the credit for the rate of change can be laid at the feet of one entrepreneur, Chief Executive Jay Flatley. Thanks largely to Flatley’s leadership, Illumina emerged as the dominant maker of DNA sequencers eight years ago and has maintained 80% market share despite an assault by several well-funded competitors.

Since 2008 Illumina’s sales and profit have both increased 147%, to $1.42 billion and $125 million, respectively, as the stock increased 617% and the company’s market capitalization reached $23 billion.

Shock Waves Damage Eyes

Thursday, August 28th, 2014

One of the defining pieces of a modern soldier’s kit is a pair of sunglasses, because those shades offer protection not only against the sun but against ballistic fragments. Fragments aren’t the only danger though. It turns out that shock waves alone can damage eyes:

A new study by the University of Texas San Antonio and U.S. Army Institute of Surgical Research has found that blast waves themselves — not just the dirt and debris propelled by the blast — can cause significant and permanent damage to the eyes.

In an experiment that had the scientists blasting away at pig eyes with a high-powered air cannon, researchers learned the shock wave alone can damage portions of the eye, including the sclera — the white part — the retina, the optic nerve and more.

Among the most commonly seen injuries in the blasted porcine eyeballs was retinal detachment.

“Detachment is more common to older adults. But two clinicians on our team, an Army optometrist and ophthalmologist, told us this was something they were seeing in troops and couldn’t explain. That gave us the idea to look for this sort of damage in this study,” said Mathew Reilly, assistant professor of biomedical engineering at UTSA.

DoD data shows that ocular injuries account for 13 percent of all battlefield injuries and roughly 80 percent of eye injuries in combat are associated with blasts.

Scientist Shamans

Wednesday, August 27th, 2014

Frank Herbert based the Bene Gesserit “witches” of Dune in part on the scientific wizards of Isaac Asimov’s Foundation trilogy.

Herbert’s judgment on them is implicit in the way he has reversed the roles played by such scientists in Dune.

Asimov’s trilogy is set in a crumbling galactic empire, in which a “psychohistorian” named Han Seldon has analyzed with mathematical precision the forces acting upon masses of people and can predict nearly exactly what will happen hundreds and even thousands of years in the future. Seldon has set up a foundation to act in accordance with the statistical laws of psychohistory and take the necessary steps to bring about a new order from the ruins of the old. In Seldon’s vision, the Foundation will enable the rebuilding of galactic civilization in 1,000 years instead of the 10,000 years of turmoil that would otherwise be required.

The trilogy chronicles the successes of the Foundation and the complete accuracy of the long-dead Seldon’s scientific predictions, until a freak mutant is born. An empathetic superman, called “the Mule” because he is sterile, he was completely unexpected by Seldon, whose science could predict only mass dynamics and not the truly exceptional individual. The Mule shatters the Foundation’s precious new civilization in his own hungry grab for power, and is stopped only by a mysterious “second foundation” established by Seldon to study the science of the mind and to prepare for such unforeseen emergencies as the material science of the first foundation could not handle.

Herbert questioned the assumptions about science that he saw at work in Asimov’s trilogy. In a recent essay, he wrote:

History… is manipulated for larger ends and for the greater good as determined by a scientific aristocracy. It is assumed, then, that the scientist-shamans know best which course humankind should take…. While surprises may appear in these stories (e.g., the Mule mutant), it is assumed that no surprise will be too great or too unexpected to overcome the firm grasp of science upon human destiny. This is essentially the assumption that science can produce a surprise-free future for humankind.

Dune is clearly a commentary on the Foundation trilogy. Herbert has taken a look at the same imaginative situation that provoked Asimov’s classic — the decay of a galactic empire — and restated it in a way that draws on different assumptions and suggests radically different conclusions. The twist he has introduced into Dune is that the Mule, not the Foundation, is his hero.

The Bene Gesserit are clearly parallel to the “scientist-shamans” of the Foundation. Their science of prediction and control is biological rather than statistical, but their intentions are similar to those of Asimov’s psychohistorians. In a crumbling empire, they seek to grasp the reins of change. The Sisterhood sees the need for genetic redistribution — which ultimately motivates the jihad — and has tried to control that redistribution by means of their breeding program. The Kwisatz Haderach, the capstone of their plan, is not its only goal. Their overall intention is to manage the future of the race. Paul, like the Mule, is the unexpected betrayal of their planned future.

The irony is that Paul is not a freak but an inevitable product of the Bene Gesserit’s own schemes. Although he has come a generation early in the plan due to Jessica’s willfulness in bearing a son instead of a daughter, the real surprise is not his early birth but the paradox of the Sisterhood’s achievement: the planned instrument of perfect control, the Kwisatz Haderach, was designed to see further than his creators, He could not help but know the emptiness of their dreams. The universe cannot be managed; the vitality of the human race lies in its random generation of new possibilities. The only real surety is that surprises will occur. In contrast to the Foundation trilogy’s exaltation of rationality’s march to predicted victory, Dune proclaims the power and primacy of the unconscious and the unexpected in human affairs. Paul’s wild ride on the jihad, not the careful Bene Gesserit gene manipulation, provides the answer to the Empire’s needs.

Even though Dune so clearly undercuts the assumptions about science applauded in the Foundation trilogy, such antirationalism was the culmination of a long struggle. Early on, Herbert saw that the same assumptions pervaded much of science fiction, including his own. In order to embody his visions of the future, he needed to untangle himself from their hold.

Knickebein

Monday, August 25th, 2014

A couple years ago Gregory Cochran mentioned The Wizard War, R. V. Jones’ account of his time leading scientific intelligence for Britain during the war, because it had some interesting examples of thick and thin problems — but mostly because it’s so damn much fun.

I bought a copy, under the original British title, Most Secret War — “most secret” is the British equivalent of “top secret” — and recently read and enjoyed it.

The classically thin problem that Cochran cites involves the German two-beam navigation system (Knickebein). From page 97 of my copy:

It may help here if I explain what a Lorenz beam is, for this is what we expected to find. If one arranges a number of aerial units (‘dipoles’, which look like the simplest type of television aerial) side by side, as in a fence and about the same distance apart as they are long, and feeds the radio energy to them in a suitable manner they will generate the beam which emerges broadside to the fence; and, paradoxically perhaps, the longer the ‘fence’ the sharper the beam. But without a fence of prohibitive length, the beam would not be nearly sharp enough to define a target one mile wide at two hundred miles range. The clever trick in the Lorenz system was to transmit two fairly blunt beams, pointing in slightly different directions but overlapping one another in a relatively narrow region which now in effect becomes the ‘beam’ along which the aircraft are intended to fly.

Knickebein Principle of the Lorenz Beam Diagram

The two overlapping beams are most simply generated by two aerial systems pointing in slightly different directions and mounted together on a single turntable. The actual radio transmitter is switched from one of these aerials to the other and back again in a repetitive sequence, so that one aerial transmits for a short time followed by a longer interval, giving a ‘dot’ to anyone who listens to it on a suitable radio receiver, while the other transmits for a long time followed by a short interval, giving a ‘dash’. Anyone so placed as to receive the two aerials at the same strength would hear the one transmit a dot immediately followed by the other transmitting a dash, so that he would think that he was listening to a single aerial transmitting continuously. As he moved sideways into the zone in which one beam, say the ‘dot’ beam, was stronger than the other, he would being to hear the dots coming up above the continuous note, and vice versa with the dashes. By listening for the predominance of dots or dashes he would know the direction in which he would have to steer to bring himself back into the narrow ‘equi-signal’ zone. This zone can be as narrow as one hundredth or even one thousandth of the width of the ‘dot’ or ‘dash’ beam alone.  The aerials are therefore set on the turntable in such a direction that the equi-signal zone passes over the target.  To warn the pilot that he is approaching the target, a similar beam system would be set up from one site well to the side of the director beam, and this second system would transmit a marker beam to cross the director a few kilometres before the target.