Zebra stripes are unique to each individual zebra, reports LiveScience, in an article shared by long-time Slashdot reader fahrbot-bot. And even if you look at the three different zebra species, their skin is always the same color: black (according to Tim Caro, a behavioral and evolutionary ecologist and conservation biologist at the University of California, Davis).

But this still doesn’t answer the question of whether their fur is black with white stripes or white with black stripes.

For that, we have to look to the zebra’s melanocytes, or the cells that produce pigment for their fur. Although zebras have black skin, different developmental processes determine their fur color, just like a light-skinned person can have dark hair, Caro said. In fact, zebras actually have more light-colored hair than dark — their bellies are usually light — so it may seem that zebras are white with black stripes.

But that’s not the case. Here’s why: Every piece of hair — both light and dark — grows from a follicle filled with melanocyte cells, according to a 2005 review in the Journal of Investigative Dermatology. These cells produce a pigment that determines the color of hair and skin. This pigment is known as melanin; a lot of melanin leads to darker colors, like dark brown or black, while less melanin leads to lighter colors, such as hazel or blond, Live Science previously reported. Zebras’ black fur is chock-full of melanin, but melanin is absent from white fur, in essence, because the follicles that make up the stripes of white hair have “turned off” melanocytes, meaning they don’t churn out pigment.

The production of melanin from melanocytes is “prevented during the development of a white hair, but not of a black hair,” Caro told Live Science in an email. In other words, for zebras, the animals’ default state is to produce black hair, making them black with white stripes, according to Brittanica….

This unique pattern may keep away biting flies, according to research by Caro and his colleagues. In a study published in 2020 in the journal Proceedings of the Royal Society B, they found that African horseflies landed less frequently on horses wearing striped or checked rugs than they did on horses wearing solid-colored rugs. These biting flies can carry diseases that are fatal to zebras.

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Source: Slashdot – Are Zebras White With Black Stripes Or Black With White Stripes?

The president emeritus of the Great Lakes College Association writes that “nearly all colleges have re-adopted in-person education this fall, in spite of delta variant risks…

“As it turns out, student enthusiasm for remote learning is mixed at best, and in some cases students have sued their colleges for refunds. But it is not simply student opinion that has driven this reversion to face-to-face education.”

Indeed, students are far better off with in-person learning than with online approaches. Recent research indicates that the effects of remote learning have been negative. As the Brookings Institution Stephanie Riegg reports, “bachelor’s degree students in online programs perform worse on nearly all test score measures — including math, reading, writing, and English — relative to their counterparts in similar on-campus programs….”

[R]esearch on human learning consistently finds that the social context of learning is critical, and the emotions involved in effective human relations play an essential role in learning. Think of a teacher who had a great impact on you — the one who made you excited, interested, intrigued, and motivated to learn. Was this teacher a calm and cool transmitter of facts, or a person who was passionate about the subject and excited to talk about it…? Research tells us the most effective teachers — those who are most successful in having their students learn — are those who establish an emotional relationship with their students in an environment of care and trust. As former teacher and now neuroscientist Mary Helen Immordino-Yang tells us, emotion is necessary for learning to occur: “Emotion is where learning begins, or, as is often the case, where it ends. Put simply, it is literally neurobiologically impossible to think deeply about things that you don’t care about…. Even in academic subjects that are traditionally considered unemotional, such as physics, engineering or math, deep understanding depends on making emotional connections between concepts….”

Today we have the benefit of extensive research documenting the short-term and long-term importance of these social-educational practices. Research based on the widely used National Survey of Student Engagement (NSSE) consistently finds that having meaningful outside-of-class relationships with faculty and advisors increases not only learning but graduation from college and employment after graduation. It is also worth noting that Gallup-Purdue University public opinion research affirms the idea that people believe these personal relationships in college matter. A study of 30,000 graduates reports that they believe “what students are doing in college and how they are experiencing it… has a profound relationship to life and career.” Specifically, “if graduates had a professor who cared about them as a person, made them excited about learning, and encouraged them to pursue their dreams, their odds of being engaged at work more than doubled, as did their odds of thriving in their well-being.”

Since empirical research documents the powerful impact of meaningful human relationships on learning while in college as well as on graduate’s adult lives, and people believe it matters, do we dare replace it with technology?

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Source: Slashdot – Why Colleges are Giving Up on Remote Education

An anonymous reader writes: Given the widespread understanding that sophisticated hackers are regularly using zero-day vulnerabilities to break into high-value systems, why is it that when I search for “zero day” on Australia’s most popular job search engine only one “real” job comes up? Is the security of the Internet totally dependent on dedicated hobbyists, part-time showboats, and people willing to take meagre bug bounties (on average paying $3,650 for a critical vulnerability) instead of selling their findings (sometimes for millions of dollars) to dubious buyers?

Are they all in-house security people hunting for zero-days as part of their regular responsibilities? Share your own thoughts in the comments.
Where are all the jobs preventing zero-day exploits?

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Source: Slashdot – Ask Slashdot: Where Are All the Jobs Preventing Zero-Day Exploits?

“In a rock concert-like atmosphere, El Salvador President Nayib Bukele announced that his government will build an oceanside ‘Bitcoin City’ at the base of a volcano…” reports the Associated Press.

“A bond offering would happen in 2022 entirely in Bitcoin, Bukele said, wearing his signature backwards baseball cap. And 60 days after financing was ready, construction would begin.”

The city will be built near the Conchagua volcano to take advantage of geothermal energy to power both the city and Bitcoin mining — the energy-intensive solving of complex mathematical calculations day and night to verify currency transactions. The government is already running a pilot Bitcoin mining venture at another geothermal power plant beside the Tecapa volcano…

The government will provide land and infrastructure and work to attract investors. The only tax collected there will be the value-added tax, half of which will be used to pay the municipal bonds and the rest for municipal infrastructure and maintenance. Bukele said there would be no property, income or municipal taxes and the city would have zero carbon dioxide emissions.

“Invest here and earn all the money you want,” Bukele told the cheering crowd in English at the closing of the Latin American Bitcoin and Blockchain Conference being held in El Salvador.

CNN adds some interesting details:
Likening his plan to cities founded by Alexander the Great, Bukele said Bitcoin City would be circular, with an airport, residential and commercial areas, and feature a central plaza designed to look like a bitcoin symbol from the air. “If you want bitcoin to spread over the world, we should build some Alexandrias,” said Bukele, a tech savvy 40-year-old who in September proclaimed himself “dictator” of El Salvador on Twitter in an apparent joke.

El Salvador plans to issue the initial bonds in 2022, Bukele said, suggesting it would be in 60 days time. Samson Mow, chief strategy officer of blockchain technology provider Blockstream, told the gathering the first 10-year issue, known as the “volcano bond”, would be worth $1 billion, backed by bitcoin and carrying a coupon of 6.5% [the annual interest paid on a bond]. Half of the sum would go to buying bitcoin on the market, he said. Other bonds would follow. After a five year lock-up, El Salvador would start selling some of the bitcoin used to fund the bond to give investors an “additional coupon”, Mow said, positing that the value of the cryptocurrency would continue to rise robustly.
“This is going to make El Salvador the financial center of the world,” he said…
Once 10 such bonds were issued, $5 billion in bitcoin would be taken off the market for several years, Mow said. “And if you get 10 more countries to do these bonds, that’s half of bitcoin’s market cap right there.” The “game theory” on the bonds gave first issuer El Salvador an advantage, Mow argued, saying: “If bitcoin at the five-year mark reaches $1 million, which I think it will, they will sell bitcoin in two quarters and recoup that $500 million.”

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Source: Slashdot – El Salvador Plans ‘Bitcoin City’ Powered by a Volcano, Financed by Bitcoin Bonds