A Parasite, Leopards, and a Primate’s Fear and Survival

A Parasite, Leopards, and a Primate’s Fear and Survival
By Carl Zimmer
Feb 11 2016

Many of our primate ancestors probably ended up in the bellies of big cats. How else to explain bite marks on the bones of ancient hominins, the apparent gnawing of leopards or other African felines?

Big cats still pose a threat to primates. In one study of chimpanzees in Ivory Coast, for example, scientists estimated that each chimp ran a 30 percent risk of being attacked by a leopard every year.

A new study suggests that the big cats may be getting some tiny help on the hunt. A parasite infecting the brains of some primates, including perhaps our forebears, may make them less wary.

What does the parasite get out of it? A ride into its feline host.

The parasite is Toxoplasma gondii, a remarkably successful single-celled organism. An estimated 11 percent of Americans have dormant Toxoplasma cysts in their brains; in some countries, the rate is as high as 90 percent. Infection with the parasite poses a serious threat to fetuses and to people with compromised immune systems. But the vast majority of those infected appear to show no serious symptoms. Their healthy immune systems keep the parasite in check.

Mammals and birds can also be infected. But cats in particular play a crucial part in the life cycle of the parasite: When a cat eats an infected animal, Toxoplasma gondii ends up in its gut. It reproduces there, generating offspring called oocysts that are shed in the cat’s feces. The oocysts can last for months in the environment, where they can be taken up by new hosts.

In the 1990s, scientists discovered that mice and rats infected with Toxoplasma gondii lose their natural fear of cat odors — and in some cases even appear to become attracted to them. It was possible, researchers speculated, that the parasite had evolved an ability to influence the behavior of its rodent hosts, to raise the chances they might be eaten by cats.

Subsequent studies have shown that the parasite can change the wiring of fear-related regions of the rat brain. Robert M. Sapolsky, a biologist at Stanford University, said that these findings led many researchers to see Toxoplasma gondii as a parasite exquisitely adapted to rodents. According to this view, he said, “Toxo being able to infect a zillion nonrodent species is just some sort of irrelevant evolutionary dead end.”

Even so, Toxoplasma gondii can cause intriguing changes in our brains as well. In a 2015 study, for example, researchers found that women infected with the parasite are more aggressive than those without it; infected men behave more impulsively than parasite-free men.

Clémence Poirotte, an evolutionary biologist at the Center for Functional and Evolutionary Ecology in Montpellier, France, wondered if our understanding of Toxoplasma might be limited by the paltry number of species in which its manipulations had been studied. She and her colleagues decided to focus on chimpanzees, running an experiment on 33 apes at a primate research center in Gabon, nine of which had Toxoplasma infections.

Instead of testing the reactions of chimpanzees to the odor of house cats, Ms. Poirotte and her colleagues turned to leopards, their natural predators. A veterinarian at a Gabon zoo supplied them with leopard urine, and they poured drops of it on the fence enclosing the space in which the chimpanzees lived.

Stepping back from the fence, the scientists observed the apes to see how they responded. They also ran the same experiment with urine from three species that are not chimpanzees’ natural predators: humans, lions and tigers.

Sometimes, the chimpanzees would approach the fence and investigate the smell; other times, they would ignore it. Ms. Poirotte and her colleagues found that chimpanzees not infected with Toxoplasma investigated the smell of leopard urine less than the smell of humans.


The Faces of American Power, Nearly as White as the Oscar Nominees

The Faces of American Power, Nearly as White as the Oscar Nominees
Feb 26 2016

We reviewed 503 of the most powerful people in American culture, government, education and business, and found that just 44 are minorities. Any list of the powerful is subjective, but the people here have an outsize influence on the nation’s rules and culture.


What It’s Really Like to Risk It All in Silicon Valley

What It’s Really Like to Risk It All in Silicon Valley
By Claire Cain Miller
Feb 27 2016

Before Nathalie Miller decided to walk away from Instacart, the grocery delivery start-up now worth more than $2 billion, she made a spreadsheet to analyze how much money she was leaving on the table.

She had been Instacart’s 20th employee, managing operations during a period of extremely rapid growth, and the sum could have been huge. She quit anyway. Like many strivers in Silicon Valley, she had a bigger plan: to start her own company that could not only make millions, but also fulfill a mission she believed in.

Her idea was to build a recruiting and hiring website that would make corporate America friendlier to women. She called the site Doxa and persuaded an engineer friend to start it with her. They strategized in borrowed office space and recruited people from other tech companies to work on the project at night, promising full-time salaries as soon as they raised venture capital.

Then, six months later, Ms. Miller discovered that she was pregnant with her first child. A baby wasn’t something she and her husband, Isaak Le, had been planning quite yet, but they were excited. Still, a sliver of doubt began to undercut her confidence about starting her own company. “How high can I stack the cards against myself — a pregnant brown woman?” said Ms. Miller, who is of Vietnamese and European descent.

Silicon Valley can seem like the land of overnight success. College dropouts show up and become billionaires a few years later. Mark Zuckerberg was a billionaire by the time he was 23, and Facebook paid $19 billion for WhatsApp when it was just five years old.

But despite their hold on the imagination, these examples aren’t typical. Much more representative are the companies you never hear about because they never get off the ground.

Venture capital firms invest in 1 percent of the companies that pitch them. The overwhelming majority of entrepreneurs who are funded are white men. Just 1 percent are black, 8 percent are female and 12 percent are Asian, according to data from CB Insights, which tracks private companies and investors. Even for start-ups that raise money, the mortality rate is high, with most dying after an average of 20 months and $1.3 million in financing.

In recent months, the fund-raising atmosphere has cooled as venture capitalists react to the poor stock market performance of some public tech companies and question whether the recent fast pace of investment is sustainable. Venture capitalists are making fewer investments at lower valuations.

“There is this delusion that it’s easy to raise money in Silicon Valley,” said Sam Altman, president of Y Combinator, a mentorship and investment program for start-ups. “Raising money is incredibly hard.”

Nonetheless, Silicon Valley keeps seducing people. For those who come, the risk is worth the potential reward — not just riches, but also the more dreamy belief that tech entrepreneurialism is a force for good. Ms. Miller was not immune.

“I want Doxa to exist in the world,” she told me in July, “because it will make the world a better place.”


The Wrong Way to Teach Math

The Wrong Way to Teach Math
Feb 27 2016

HERE’S an apparent paradox: Most Americans have taken high school mathematics, including geometry and algebra, yet a national survey found that 82 percent of adults could not compute the cost of a carpet when told its dimensions and square-yard price. The Organization for Economic Cooperation and Development recently tested adults in 24 countries on basic “numeracy” skills. Typical questions involved odometer readings and produce sell-by tags. The United States ended an embarrassing 22nd, behind Estonia and Cyprus. We should be doing better. Is more mathematics the answer?

In fact, what’s needed is a different kind of proficiency, one that is hardly taught at all. The Mathematical Association of America calls it “quantitative literacy.” I prefer the O.E.C.D.’s “numeracy,” suggesting an affinity with reading and writing.

Calculus and higher math have a place, of course, but it’s not in most people’s everyday lives. What citizens do need is to be comfortable reading graphs and charts and adept at calculating simple figures in their heads. Ours has become a quantitative century, and we must master its language. Decimals and ratios are now as crucial as nouns and verbs.

It sounds simple but it’s not easy. I teach these skills in an undergraduate class I call Numeracy 101, for which the only prerequisite is middle school arithmetic. Even so, students tell me they find the assignments as demanding as rational exponents and linear inequalities.

I’m sometimes told that what I’m proposing is already being covered in statistics courses, which have growing enrollments both in high schools and colleges. In 2015, nearly 200,000 students were taking advanced placement classes in statistics, over three times the number a dozen years ago. This might suggest we are on the way to creating a statistically sophisticated citizenry.

So I sat in on several advanced placement classes, in Michigan and New York. I thought they would focus on what could be called “citizen statistics.” By this I mean coping with the numbers that suffuse our personal and public lives — like figures cited on income distribution, climate change or whether cellphones can damage your brain. What’s needed is a facility for sensing symptoms of bias, questionable samples and dubious sources of data.

My expectations were wholly misplaced. The A.P. syllabus is practically a research seminar for dissertation candidates. Some typical assignments: binomial random variables, least-square regression lines, pooled sample standard errors. Many students fall by the wayside. It’s not just the difficulty of the classes. They can’t see how such formulas connect with the lives they’ll be leading. Fewer than a third of those enrolled in 2015 got grades high enough to receive credit at selective colleges.

Something similar occurred when the Carnegie Foundation for the Advancement of Teaching created a statistics course for 19 community colleges in 2012. It was advertised as an alternative to remedial algebra, with its sadistic attrition rates. In Statways, as it was called, here is some of what students were asked to master: chi-square test for homogeneity in two-way tables, line multiple representation of exponential models. Even with small classes and extra support, almost half of the students got D’s or F’s or dropped the class.


The ISIS Intel scandal just got real

[Note:  This item comes from friend David Rosenthal.  DLH]

The ISIS Intel scandal just got real
By gjohnsit
Feb 27 2016

The House intelligence committee just accused the Pentagon of a cover-up, and this may turn into the first major scandal in the War on ISIS.

Committee Chairman Devin Nunes of California blasted the Pentagon, citing the allegations that classified intelligence files and emails about the war on ISIS were deleted.

  “We have been made aware that both files and emails have been deleted by personnel at CENTCOM, and we expect that the Department of Defense will provide these and all other relevant documents to the committee,” Nunes said at a hearing Thursday on worldwide threats…

  Nunes’ assertions led to an extraordinary public acknowledgment from Lt. Gen. Vincent Stewart, director of the Defense Intelligence Agency, who was testifying before the committee, of the “unusually high” dissatisfaction inside the agency responsible for providing military intelligence on ISIS.

 The Defense Department Inspector General is already investigating allegations that military intelligence was skewed to show positive results in the war.   

If this sounds suspiciously like Vietnam in 1967 and Iraq in 2003, it’s because it is a lot like it. Democratic administration. Republican administration. When it comes to war there doesn’t seem to be much difference in regards to slanting intelligence.

 So what sort of slanting are we talking about? Something like this.

When Islamic State fighters overran a string of Iraqi cities last year, analysts at United States Central Command wrote classified assessments for military intelligence officials and policy makers that documented the humiliating retreat of the Iraqi Army. But before the assessments were final, former intelligence officials said, the analysts’ superiors made significant changes.

 In the revised documents, the Iraqi Army had not retreated at all. The soldiers had simply “redeployed.”

 That redeployment involved tens of thousands of soldiers throwing away their guns, taking off their uniforms, and running for their lives. The Iraqi Army has still not recovered from this epic collapse nearly two years later.    Fortunately, Pentagon whistleblowers came forward with documents and evidence of this naked deception.

“The cancer was within the senior level of the intelligence command,” one defense official said.

  Two senior analysts at CENTCOM signed a written complaint sent to the Defense Department inspector general in July alleging that the reports, some of which were briefed to President Obama, portrayed the terror groups as weaker than the analysts believe they are. The reports were changed by CENTCOM higher-ups to adhere to the administration’s public line that the U.S. is winning the battle against ISIS and al Nusra, al Qaeda’s branch in Syria, the analysts claim.

  That complaint was supported by 50 other analysts, some of whom have complained about politicizing of intelligence reports for months.


Buffett: Candidates Wrong About the Economy

[Note:  This item comes from friend Mike Cheponis.  DLH]

Buffett: Candidates Wrong About the Economy
They’re exaggerating how bad it is, he complains
By Newser Editors and Wire Services
Feb 27 2016

Newser) – The US economy is in better shape than the presidential candidates make it seem, investor Warren Buffett said Saturday. In his annual letter to Berkshire Hathaway shareholders, Buffett didn’t name specific candidates or issues, but noted that the negative drumbeat about the economy, health care reform, and income inequality may get voters down about the future, reports AP. “It’s an election year, and candidates can’t stop speaking about our country’s problems (which, of course, only they can solve),” he said. “That view is dead wrong: The babies being born in America today are the luckiest crop in history.”

Buffett’s letter—read it in full here—is one of the most well-read documents in the business world each year because of his successful track record and his knack for explaining complicated subjects in simple terms. The Wall Street Journal is parsing it as well, observing that Buffett “brushes past last year’s disappointing stock performance, dwells on Berkshire’s ties to private-equity firm 3G, talks about Berkshire’s big 2015 deal, and defends manufactured -housing unit Clayton Homes.” Buffett said the book value of Berkshire’s businesses improved 6.4% last year even as its stock price fell 12.5%.