The Tibetans do things differently

Saturday, May 20th, 2017

Tibetans have evolved and maintained genetic adaptations that suit them to life above 15,000 feet:

Huff and co-authors published a study in April in PLOS Genetics analyzing for the first time whole-genome sequences for 27 Tibetan individuals. The research identified three new genes that help with mountain living, in addition to confirming two that were previously known. These gene variants give Tibetans the ability to metabolize oxygen more efficiently and protect against Vitamin D deficiency.

[...]

One of the genes that helps Tibetans adapt to high altitude is known as EPAS1. The Tibetan variant of this gene does a surprising thing — it actually lowers the hemoglobin count in your blood at high altitudes. Hemoglobins are a protein in red blood cells that transport oxygen to your body. It’s surprising that Tibetans would have a lower hemoglobin count at high altitudes; normally our bodies respond to lower oxygen pressures by increasing hemoglobins in our blood, allowing for more O2 to reach the muscles. It’s even more surprising because other population groups that have adapted to high altitude environments, including the South American Andes and Africa’s Ethiopian Highlands, have done so in part by raising hemoglobin count.

The Tibetans, however, do things differently. Rather than upping hemoglobin count, their bodies have several adaptations that allow them to use oxygen more efficiently, so they need less of it. This allows them to keep hemoglobin counts relatively low at high altitude, which helps to avoid some of the potential downsides of a high hemoglobin count. Hemoglobins thicken the blood, and the thicker your blood the more likely it is to clot, which increases the risk of heart disease and stroke.

A parable of the lessons that can emerge from unfettered science

Tuesday, May 16th, 2017

I was immediately fascinated by the Siberian farm fox experiment and the surprisingly broad domestication phenotype, which notably includes pigmentation.

Marlene Zuk reviews Dugatkin and Trut’s How to Tame a Fox (and Build a Dog) for The New York Times, and ends on this note:

The book, however, is not only about dogs, or foxes, or even science under siege from political interests. It is an exploration of how genes, evolution and then environment shape behavior, and in a way that puts paid simplistic arguments about nature versus nurture. It may serve — particularly now — as a parable of the lessons that can emerge from unfettered science, if we have the courage to let it unfold.

Marlene Zuk wrote Paleofantasy: What Evolution Really Tells Us About Sex, Diet and How We Live.

There is a difficulty with giving The Bell Curve a chance

Friday, May 12th, 2017

Charles Murray explains his controversial book The Bell Curve:

In April, I recorded an interview of almost two and a half hours with Sam Harris for his Waking Up podcast, which, I learned only after I had done it, regularly attracts a few million listeners. We spent more than half of the interview discussing what is actually in “The Bell Curve” as opposed to what people think is in it. Both of us expected our Twitter feeds to light up with nasty reactions after the interview was posted. But the opposite happened. The nasty reactions were far outnumbered by people who said they had always assumed that “The Bell Curve” was the hateful pseudoscientific mess that the critics had claimed, but had now decided they wanted to give the book a chance. It has been a heartening experience.

However, there is a difficulty with giving “The Bell Curve” a chance. The paperback edition has 26 pages of front material, 552 pages of main text, a 23-page response to the critics, 111 pages of appendixes, another 111 pages of endnotes, and a 58-page bibliography. It’s a lot to get through. But there’s a shorter way to get a good idea of what’s in the book: Dick Herrnstein and I began each chapter with a summary that was usually about a page long. With the publisher’s permission, I have stitched all of those summaries together, along with selections from the Introduction and the openings to each of the four parts of the book. If these tidbits arouse enough interest that you buy the book, I will be delighted. But at this point in my life, my main objective is that a labor of love, written with a friend who I still miss twenty-three years after his death, be seen for what it is.

Chronotherapy

Tuesday, May 9th, 2017

Keeping the body’s cells synced up matters for health:

In 2007, based on epidemiological studies, the International Agency for Research on Cancer declared shift work, which causes circadian disruption, a carcinogen. Other studies have elucidated a link between immune cell activity and glucocorticoids—which are secreted in circadian patterns and regulate peripheral clocks—as well as a role for chronic stress in perturbing daily cycles in gene expression, which can alter immune, endocrine, and other functions.

[...]

Genes involved in cell division were among the earliest identified as being rhythmically expressed in both rodent models and human cells. In 1987, researchers studying ovarian cancers found that tumor cells synthesized DNA on a daily rhythm that typically peaked in the late morning hours, nearly 12 hours out of sync with nontumor cells. This led the team to suggest that timing chemotherapy doses that target cells actively replicating their DNA might improve the drugs’ effectiveness while reducing healthy-cell death.

Sure enough, over the past 30 years, experimental models and clinical trials have found that timing chemo regimens can significantly affect their toxicity and effectiveness. In animal studies of nearly 30 chemo drugs, tailoring dosing time to the medication’s mode of action has been found to decrease toxic side effects and increase effectiveness. In one study, rats that received the chemotherapy drug cisplatin at the time of day when their urinary output was highest (a correlate of other timed cycles in kidney metabolism) had fewer nephrotoxic effects, as measured in kidney function tests, than animals that received the doses at the time of minimum urinary output. In another study, oxaliplatin chemotherapy caused fewer intestinal lesions and less bone marrow suppression in mice when given at night, possibly because DNA synthesis in murine bone marrow is highest during the day.

[...]

Clinical trials in 1985 found that antihistamines were most effective when taken at night or early in the morning. Subsequent studies established that inhaling corticosteroids at bedtime, or using delayed-release prednisone formulations that allocated the medication to the body pre-dawn, were most effective at combating allergy symptoms. Cardiovascular events were also recognized early on to cycle throughout the day, as doctors noticed that most patients admitted for heart attacks tended to experience their symptoms between 6:00 a.m. and noon.

Ancient vulture stone carvings confirm comet strike

Saturday, May 6th, 2017

Scientists have speculated for decades that a comet could be behind the sudden fall in temperature during a period known as the Younger Dryas:

But recently the theory appeared to have been debunked by new dating of meteor craters in North America where the comet is thought to have struck.

However, when engineers studied animal carvings made on a pillar – known as the vulture stone – at Gobekli Tepe they discovered that the creatures were actually astronomical symbols which represented constellations and the comet.

The idea had been originally put forward by author Graham Hancock in his book Magicians of the Gods.

Using a computer programme to show where the constellations would have appeared above Turkey thousands of years ago, they were able to pinpoint the comet strike to 10,950BC, the exact time the Younger Dryas begins according to ice core data from Greenland.

Position of the sun and stars on the summer solstice of 10,950BC

The Younger Dryas is viewed as a crucial period for humanity, as it roughly coincides with the emergence of agriculture and the first Neolithic civilisations.

Before the strike, vast areas of wild wheat and barley had allowed nomadic hunters in the Middle East to establish permanent base camps. But the difficult climate conditions following the impact forced communities to come together and work out new ways of maintaining the crops, through watering and selective breeding. Thus farming began, allowing the rise of the first towns.

Edinburgh researchers said the carvings appear to have remained important to the people of Gobekli Tepe for millennia, suggesting that the event and cold climate that followed likely had a very serious impact.

Graham Hancock appeared on Joe Rogan Experience #872 and #725.

Thomas Henry Huxley

Thursday, May 4th, 2017

While pop-culture geeks are saying, “May the Fourth be with you,” science geeks might celebrate Thomas Henry Huxley‘s birthday:

He became one of the great autodidacts of the nineteenth century. At first he read Thomas Carlyle, James Hutton’s Geology, and Hamilton’s Logic. In his teens he taught himself German, eventually becoming fluent and used by Charles Darwin as a translator of scientific material in German. He learned Latin, and enough Greek to read Aristotle in the original.

Later on, as a young adult, he made himself an expert, first on invertebrates, and later on vertebrates, all self-taught. He was skilled in drawing and did many of the illustrations for his publications on marine invertebrates. In his later debates and writing on science and religion his grasp of theology was better than most of his clerical opponents. Huxley, a boy who left school at ten, became one of the most knowledgeable men in Britain.

Thomas Huxley drawing by his daughter Marian

He’s known for being Darwin’s bulldog, for coining the term agnostic, and for being Aldous Huxley’s grandfather.

Researchers find yet another reason why naked mole-rats are weird

Wednesday, May 3rd, 2017

Researchers find yet another reason why naked mole-rats are weird:

For example, instead of generating their own heat, they regulate body temperature by moving to warmer or cooler tunnels, which lowers the amount of energy they need to survive. They’re also known to have what Park calls “sticky hemoglobin,” which allows them to draw oxygen out of very thin air. And because they live underground in large social groups, they’re used to breathing air that’s low in oxygen and high in carbon dioxide.

[...]

To start out, he and his colleagues tested how well the mole-rats fared in a chamber with only 5 percent oxygen, which is about a quarter of the oxygen in the air we breathe, and can kill a mouse in less than 15 minutes.

They watched closely, ready to pull the mole-rats out at the first sign of trouble.

“So we put them in the chamber and after five minutes, nothing. No problems,” Park says. An hour later, there were still no problems.

Five hours later, the researchers were tired and hungry and ready to go home, but the mole-rats could’ve kept chugging along.

“Oh, I think so,” says Park. “They had more stamina than the researchers.”

The animals had slowed down a bit, he says, but were awake, walking around and even socializing.

“They looked completely fine,” he says.

Next, the researchers decided to see how the mole-rats dealt with zero percent oxygen.

“And that was a surprise, too,” he says.

Such conditions can kill a mouse in 45 seconds.

The four mole-rats involved in this leg of the study passed out after about 30 seconds, but their hearts kept beating and — a full 18 minutes later — the mole-rats woke up and resumed life as usual when they were re-exposed to normal air. (The three mole-rats that were exposed for 30 minutes, however, died.)

[...]

When the researchers looked at tissue samples taken from the mole-rats at various times during the oxygen deprivation, they noticed a spike in levels of another sugar, fructose, about 10 minutes in.

“We weren’t looking for it, but bang, fructose goes way up in the blood and then it goes way up in the organs and it gets used by heart and brain,” Park says.

The naked mole-rats appear to have the option of switching fuels from glucose, which requires oxygen to create energy, to fructose, which doesn’t.

Humans are capable of storing and using fructose in the liver and kidney, but as Park explains, we don’t have enough of the correct enzyme to create energy directly from fructose. Nor do we have enough of the proteins necessary to move fructose molecules into the cells of vital organs. Our cells have to convert it into glucose in order to use it.

The cells in the brain, heart, liver and lungs of naked mole-rats are all outfitted with proteins that moves fructose into the cells, and with the right enzyme to create energy from it.

“They have a social structure like insects, they’re cold-blooded like reptiles, and now we found that they use fructose like a plant,” Park says.

No sci-fi alien is as strange as an octopus

Tuesday, May 2nd, 2017

“No sci-fi alien is so startlingly strange” as an octopus, Sy Montgomery noted, but they’re even stranger than we realized:

Rosenthal and Eisenberg found that RNA editing is especially rife in the neurons of cephalopods. They use it to re-code genes that are important for their nervous systems — the genes that, as Rosenthal says, “make a nerve cell a nerve cell.” And only the intelligent coleoid cephalopods — octopuses, squid, and cuttlefish — do so. The relatively dumber nautiluses do not. “Humans don’t have this. Monkeys don’t. Nothing has this except the coleoids,” says Rosenthal.

It’s impossible to say if their prolific use of RNA editing is responsible for their alien intellect, but “that would definitely be my guess,” says Noa Liscovitch-Brauer, a member of Rosenthal’s team who spearheaded the new study. “It makes for a very compelling hypothesis in my eyes.”

[...]

Only about 3 percent of human genes are ever edited in this way, and the changes are usually restricted to the parts of RNA that are cut out and discarded. To the extent that it happens, it doesn’t seem to be adaptive.

In cephalopods, it’s a different story. Back in 2015, Rosenthal and Eisenberg discovered that RNA editing has gone wild in the longfin inshore squid — a foot-long animal that’s commonly used in neuroscience research. While a typical mammal edits its RNA at just a few hundred sites, the squid was making some 57,000 such edits. These changes weren’t happening in discarded sections of RNA, but in the ones that actually go towards building proteins — the so-called coding regions. They were ten times more common in the squid’s neurons than in its other tissues, and they disproportionately affected proteins involved in its nervous system.

Having been surprised by one cephalopod, the team decided to study others. Liscovitch-Brauer focused on the common cuttlefish, common octopus, and two-spot octopus. All of these showed signs of extensive RNA editing with between 80,000 to 130,000 editing sites each. By contrast, the nautilus — a ancient cephalopod known for its hard, spiral shell — only had 1,000 such sites.

This distinction is crucial. The nautiluses belong to the earliest lineage of cephalopods, which diverged from the others between 350 and 480 million years ago. They’ve stayed much the same ever since. They have simple brains and unremarkable behavior, and they leave their RNA largely unedited. Meanwhile, the other cephalopods — the coleoids — came to use RNA editing extensively, and while evolving complex brains and extraordinary behavior. Coincidence?

Liscovitch-Brauer also found that around 1,000 of the edited locations were shared between the coleoid species — far more than the 25 or so sites that are shared between humans and other mammals. These sites have been preserved over hundreds of millions of years of evolution.

Mimicking an impact on Earth’s early atmosphere yields all 4 RNA bases

Saturday, April 29th, 2017

Stanley Miller and Harold Urey performed an experiment that has become a staple of high school textbooks:

Miller and Urey are the people who sealed up a mixture of gases meant to model the Earth’s early atmosphere and jolted the gas with some sparks. What emerged was a complex mix of chemicals that included amino acids, the building blocks of proteins.

It was a seminal experiment in that it gave researchers one of the first avenues to approach the origin of life experimentally, but its relevance to the actual origin of life has faded as the research it inspired began to refine our ideas. A French-Czech team of researchers decided to give it another look, using a source of energy that Miller and Urey hadn’t considered: the impact of a body arriving from space. The result? The production of all four of the bases found in RNA, a close chemical cousin to DNA and equally essential to life.

Tough, detail-oriented, and able to push themselves

Thursday, April 27th, 2017

Jennifer Bricker was born without legs and immediately given up for adoption by her Romanian-American parents:

But with the support of her adoptive family, Jen, in spite of her physical challenges, grew to become a champion athlete herself. By age 12 she was excelling in power tumbling — an acrobatic sport that combines artistic gymnastics and trampoline. She failed to understand why people singled out her achievements over those of her teammates. In 1998, she placed fourth in the all-around event at the Junior Olympics, the first physically challenged tumbler to finish so high. Her gymnastics idol growing up? Dominique Moceanu.

Her gymnastics idol, Dominique Moceanu, was one of the “Magnificent Seven” at the 1996 Summer Olympics in Atlanta — and turned out to be her older sister.

Nancy L. Segal describes her work on identical twins and non-twin siblings:

I have studied separated twins for many years, first from 1982 to 1991 as an investigator with the Minnesota Study of Twins Reared Apart (MISTRA). Today, I follow the progress of 16 young Chinese reared-apart twin pairs, as well as older twins separated due to unusual life events. I have seen striking examples of identical, reared-apart twins whose athletic talents coincided prior to any contact between them. Japanese-born twins Steve and Tom, raised by different families in the United States, both became competitive lifters and owners of bodybuilding gyms; Steve competed in the 1980 Olympics. Adriana and Tamara, born in Mexico and raised in New York, attended different Long Island colleges and found each other only after one was mistaken for the other. But both were already accomplished dancers and later performed together. Mark and Jerry, each six-foot-four, were both already volunteer firefighters when they met in their early thirties, each having developed the strength, stamina, and motivation to pursue the demanding role.

Studying twins, particularly separated-at-birth pairs, and separately reared non-twin siblings, is the best way to disentangle the genetic and environmental influences on individual similarities and differences. For example, such research could help determine if nature or nurture is the stronger factor in sports participation and achievement. But other physical actions and routines appear to have a genetic basis as well. Most reared-apart identical twins in the MISTRA group, for example, positioned their bodies the same way while standing for unposed photographs, which occurred less often among fraternal reared-apart pairs.

[...]

A 2005 twin study by Dutch researcher Janine Stubbe showed that genetic effects on sports participation increase after adolescence, as children gain the freedom to enter and create environments compatible with their genetic proclivities. Her subsequent 2006 study confirmed this finding, and numerous twin studies from around the world have found similar genetic effects on oxygen uptake, anaerobic capacity and power, cardiac mass, and other performance-related fitness characteristics.

Claude Bouchard of the Pennington Biomedical Research Center in Baton Rouge, Louisiana, is one of the few researchers to combine twins and adoptees in genetic studies of sports-related traits. His 1984 study of submaximal physical working capacity — an index of aerobic metabolism and oxygen transport that boosts muscular activity and endurance — found the greatest resemblance between identical twins, followed by fraternal twins, biological siblings, and adoptive siblings and showed strong genetic influence on these traits. These findings have serious implications for how we make the most of our physical abilities and overcome our limitations.

[...]

Dominique and Jen are both extroverted, driven, and competitive. They are also perfectionists and “performance hams” who love being in front of a crowd. Their voices sound the same, whether speaking or laughing, and they use their hands a lot in conversation. Jen recognizes traits in Dominique that she sees in herself, such as leadership and initiative. Both are tough, detail-oriented, and able to push themselves emotionally and physically, perhaps explaining their commitment to the long hours and personal sacrifices required for success in gymnastics.

According to Dominique, though, an important difference between them is that Jen has “super-high confidence, whereas we were beaten down by our father. I walked on eggshells.” Jen herself credits her competitive success and self-esteem to the support of her adoptive family and community — and now to the DNA she shares with her sisters as well.

[...]

My reared-apart twin research reveals that close relationships can develop quickly between such pairs. In 2003, I found that over 70 percent of reunited identical twins and nearly 50 percent of reunited fraternal twins recalled feeling closer than or as close as best friends upon first meeting. These figures jumped to about 80 percent and 65 percent, respectively, for the closeness they reported feeling when surveyed. Yet only about 20 percent of the twins felt the same way toward unrelated siblings they had always known. In 2011, I reported my findings that most parents of young separated twins observed an immediate rapport between the children when reunited. These findings suggest that perceptions of similarity (mostly behavioral) are the social glue that draws and keeps reunited twins and siblings together, underlining the universal importance of family.

Sam Harris interviews Charles Murray

Tuesday, April 25th, 2017

Sam Harris interviews Charles Murray and admits that he assumed there was something to the accusations against Murray, until he went through his own witch trials and read Murray’s work.

They weren’t cogitating, recollecting, differentiating

Tuesday, April 25th, 2017

Radiologists were asked to evaluate X-rays while inside an MRI machine that could track their brain activity:

(There’s a marvellous series of recursions here: to diagnose diagnosis, the imagers had to be imaged.) X-rays were flashed before them. Some contained a single pathological lesion that might be commonly encountered — perhaps a palm-shaped shadow of a pneumonia, or the dull, opaque wall of fluid that had accumulated behind the lining of the lung. Embedded in a second group of diagnostic images were line drawings of animals; within a third group, the outlines of letters of the alphabet. The radiologists were shown the three types of images in random order, and then asked to call out the name of the lesion, the animal, or the letter as quickly as possible while the MRI machine traced the activity of their brains. It took the radiologists an average of 1.33 seconds to come up with a diagnosis. In all three cases, the same areas of the brain lit up: a wide delta of neurons near the left ear, and a moth-shaped band above the posterior base of the skull.

“Our results support the hypothesis that a process similar to naming things in everyday life occurs when a physician promptly recognizes a characteristic and previously known lesion,” the researchers concluded. Identifying a lesion was a process similar to naming the animal. When you recognize a rhinoceros, you’re not considering and eliminating alternative candidates. Nor are you mentally fusing a unicorn, an armadillo, and a small elephant. You recognize a rhinoceros in its totality — as a pattern. The same was true for radiologists. They weren’t cogitating, recollecting, differentiating; they were seeing a commonplace object. For my preceptor, similarly, those wet rales were as recognizable as a familiar jingle.

In 1945, the British philosopher Gilbert Ryle gave an influential lecture about two kinds of knowledge. A child knows that a bicycle has two wheels, that its tires are filled with air, and that you ride the contraption by pushing its pedals forward in circles. Ryle termed this kind of knowledge — the factual, propositional kind — “knowing that.” But to learn to ride a bicycle involves another realm of learning. A child learns how to ride by falling off, by balancing herself on two wheels, by going over potholes. Ryle termed this kind of knowledge — implicit, experiential, skill-based — “knowing how.”

The two kinds of knowledge would seem to be interdependent: you might use factual knowledge to deepen your experiential knowledge, and vice versa. But Ryle warned against the temptation to think that “knowing how” could be reduced to “knowing that” — a playbook of rules couldn’t teach a child to ride a bike. Our rules, he asserted, make sense only because we know how to use them: “Rules, like birds, must live before they can be stuffed.” One afternoon, I watched my seven-year-old daughter negotiate a small hill on her bike. The first time she tried, she stalled at the steepest part of the slope and fell off. The next time, I saw her lean forward, imperceptibly at first, and then more visibly, and adjust her weight back on the seat as the slope decreased. But I hadn’t taught her rules to ride a bike up that hill. When her daughter learns to negotiate the same hill, I imagine, she won’t teach her the rules, either. We pass on a few precepts about the universe but leave the brain to figure out the rest.

Some time after Lignelli-Dipple’s session with the radiology trainees, I spoke to Steffen Haider, the young man who had picked up the early stroke on the CT scan. How had he found that culprit lesion? Was it “knowing that” or “knowing how”? He began by telling me about learned rules. He knew that strokes are often one-sided; that they result in the subtle “graying” of tissue; that the tissue often swells slightly, causing a loss of anatomical borders. “There are spots in the brain where the blood supply is particularly vulnerable,” he said. To identify the lesion, he’d have to search for these signs on one side which were not present on the other.

I reminded him that there were plenty of asymmetries in the image that he had ignored. This CT scan, like most, had other gray squiggles on the left that weren’t on the right — artifacts of movement, or chance, or underlying changes in the woman’s brain that preceded the stroke. How had he narrowed his focus to that one area? He paused as the thought pedalled forward and gathered speed in his mind. “I don’t know — it was partly subconscious,” he said, finally.

“That’s what happens — a clicking together — as you grow and learn as a radiologist,” Lignelli-Dipple told me. The question was whether a machine could “grow and learn” in the same manner.

Spoiler alert: yes.

Raising beef is good for the planet

Monday, April 24th, 2017

As a longtime vegetarian and environmental lawyer, Nicolette Hahn Niman once believed that cattle had an outsize ecological footprint:

But now, after more than a decade of living and working in the business — my husband, Bill, founded Niman Ranch but left the company in 2007, and we now have a grass-fed beef company — I’ve come to the opposite view. It isn’t just that the alarm over the environmental effects of beef are overstated. It’s that raising beef cattle, especially on grass, is an environmental gain for the planet.

Let’s start with climate change. According to the Environmental Protection Agency, all of U.S. agriculture accounts for just 8% of our greenhouse emissions, with by far the largest share owing to soil management — that is, crop farming. A Union of Concerned Scientists report concluded that about 2% of U.S. greenhouse gases can be linked to cattle and that good management would diminish it further. The primary concern is methane, a potent greenhouse gas.

But methane from cattle, now under vigorous study by agricultural colleges around the world, can be mitigated in several ways. Australian research shows that certain nutritional supplements can cut methane from cattle by half. Things as intuitive as good pasture management and as obscure as robust dung beetle populations have all been shown to reduce methane.

At the same time, cattle are key to the world’s most promising strategy to counter global warming: restoring carbon to the soil. One-tenth of all human-caused carbon emissions since 1850 have come from soil, according to ecologist Richard Houghton of the Woods Hole Research Center. This is due to tillage, which releases carbon and strips the earth of protective vegetation, and to farming practices that fail to return nutrients and organic matter to the earth. Plant-covered land that is never plowed is ideal for recapturing carbon through photosynthesis and for holding it in stable forms.

Most of the world’s beef cattle are raised on grass. Their pruning mouths stimulate vegetative growth as their trampling hoofs and digestive tracts foster seed germination and nutrient recycling. These beneficial disturbances, like those once caused by wild grazing herds, prevent the encroachment of woody shrubs and are necessary for the functioning of grassland ecosystems.

Research by the Soil Association in the U.K. shows that if cattle are raised primarily on grass and if good farming practices are followed, enough carbon could be sequestered to offset the methane emissions of all U.K. beef cattle and half its dairy herd. Similarly, in the U.S., the Union of Concerned Scientists estimates that as much as 2% of all greenhouse gases (slightly less than what’s attributed to cattle) could be eliminated by sequestering carbon in the soils of grazing operations.

Grass is also one of the best ways to generate and safeguard soil and to protect water. Grass blades shield soil from erosive wind and water, while its roots form a mat that holds soil and water in place. Soil experts have found that erosion rates from conventionally tilled agricultural fields average one to two orders of magnitude greater than erosion under native vegetation, such as what’s typically found on well-managed grazing lands.

Nor are cattle voracious consumers of water. Some environmental critics of cattle assert that 2,500 gallons of water are required for every pound of beef. But this figure (or the even higher ones often cited by advocates of veganism) are based on the most water-intensive situations. Research at the University of California, Davis, shows that producing a typical pound of U.S. beef takes about 441 gallons of water per pound — only slightly more water than for a pound of rice — and beef is far more nutritious.

Eating beef also stands accused of aggravating world hunger. This is ironic since a billion of the world’s poorest people depend on livestock. Most of the world’s cattle live on land that cannot be used for crop cultivation, and in the U.S., 85% of the land grazed by cattle cannot be farmed, according to the U.S. Beef Board.

This isn’t the “PC police” talking

Sunday, April 16th, 2017

Scientific American has published an embarrassingly unscientific piece by Eric Siegel on the real problem with Charles Murray and The Bell Curve:

Attempts to fully discredit his most famous book, 1994′s “The Bell Curve,” have failed for more than two decades now. This is because they repeatedly miss the strongest point of attack: an indisputable — albeit encoded — endorsement of prejudice.

So, the science is unassailable, but we should vehemently attack an encoded endorsement of prejudice that is based on that (apparently) unassailable science? “This isn’t the ‘PC police’ talking,” he asserts, but he completely ignores what Murray explicitly says about prejudging people:

Even when the differences are substantial, the variation between two groups will almost always be dwarfed by the variation within groups — meaning that the overlap between two groups will be great. In a free society where people are treated as individuals, “So what?” is to me the appropriate response to genetic group differences. The only political implication of group differences is that we must work hard to ensure that our society is in fact free and that people are in fact treated as individuals.

Take your shoes off at the door

Tuesday, April 11th, 2017

It turns out that taking your shoes off when you come inside doesn’t just keep the carpets cleaner. It’s also healthier:

Among samples collected in homes, 26.4% of shoe soles tested positive for C. Diff, about three times the number found on the surfaces of bathrooms and kitchens.

And that’s just one bacterium. In an earlier investigation, Dr. Garey examined past studies to learn if “shoe soles are a vector for infectious pathogens.” The answer was a resounding yes.

Among the studies: Austrian researchers found at least 40% of shoes carried Listeria monocytogenes in 2015. And a 2014 German study found that over a quarter of boots used on farms carried E.coli.

“Essentially, when you wear your shoes in a house, you are bringing in everything you stepped in during the day,” says Jonathan Sexton, a laboratory manager at the Mel & Enid Zuckerman College of Public Health at the University of Arizona.

Wiping your feet, however vigorously, on a welcome mat, provides only limited help, he says. “It will remove some of the dirt, but you have to think of the person who wiped their feet before. You might be picking stuff they left behind.”

Some homeowners may worry that guests in socks or bare feet might also represent a health risk. That’s possible, Dr. Sexton says, but the inside of a shoe has far less bacteria than the outside.

Both researchers agree that the risk is muted. “Shoes in the house are not something to freak out about,” Dr. Sexton says.