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President Trump justified his decision yesterday to leave a global climate accord with debunked conservative talking points and studies funded by groups with ties to the fossil fuel industry. He claimed the Paris Agreement would make America the laughingstock of the world, costing the country 2.7 million jobs. He said China and India could build coal plants with abandon, while the United States would be forced to shutter its own. Factories would close....

The causes of infertility, which affects around 10% of couples, are often unknown, but may in some cases result from the body’s inability to produce viable gametes — also known as sperm and egg cells. The first study of the development of such ‘germ cells’ from humans could help scientists to learn how to create them in the laboratory instead. Even though the reproductive age for humans is around 15–45 years old, the precursor cells that go on to produce human eggs or sperm are formed much earlier, when the fertilized egg grows into a tiny ball of cells in the mother’s womb....

A shifty gaze, fidgety stance or sweaty palms signal a liar in classic film noirs. In real life, however, it is surprisingly difficult to recognize when someone is telling a tall tale. Even among trained professionals, the lie-detection accuracy rate is only slightly better than pure chance. And courts tend to reject polygraph evidence because the tests lack standardized questions for determining falsehoods. For better odds, discussions of questionable claims appear to be the way to go....

Thanks to advances in artificial intelligence (AI) and machine learning, computer systems can now diagnose skin cancer like a dermatologist would, pick out a stroke on a CT scan like a radiologist, and even detect potential cancers on a colonoscopy like a gastroenterologist. These new expert digital diagnosticians promise to put our caregivers on technology’s curve of bigger, better, faster, cheaper. But what if they make medicine more biased too? At a time when the country is grappling with systemic bias in core societal institutions, we need technology to reduce health disparities, not exacerbate them....

Twenty-six-year-old nurse Nina Pham is the first person to catch Ebola from an infected human on U.S. soil. Pham is now in isolation at Texas Health Presbyterian Hospital in Dallas and the U.S. Centers for Disease Control and Prevention (CDC) has launched an investigation into safety practices at the hospital where she works and is being cared for. The source of Pham’s infection is clear: She cared for Thomas Duncan after he entered the isolation ward at the hospital on September 30....

In our cover story, “Sleep Learning Gets Real,” by Ken. A. Paller and Delphine Oudiette, we focus on a topic that has long held healthy measures of both fascination and speculation for many of us: maximizing the one third of our lifetime spent in slumber. Evoking the cultural allure of the prospect, the article opens with a reference to Aldous Huxley’s 1932 classic, Brave New World, where students are, in effect, programmed overnight by their totalitarian authorities....

Key concepts Chemistry Molecules Buoyancy Density Polarity Introduction Have you sever seen a lava lamp? They might look complicated, but you can make your own using common kitchen supplies. Try this activity to find out how! Background If you look around your kitchen, there are probably a lot of different liquids, including water, juice, milk and oil. Many of these liquids have different properties that you can see, feel and taste....

In 1926 a cargo ship called the Buckau crossed the Atlantic sporting what looked like two tall smokestacks. But these towering cylinders were actually drawing power from the wind. Called Flettner rotors, they were a surprising new invention by German engineer Anton Flettner (covered at the time in Scientific American). When the wind was perpendicular to the ship’s course, a motor spun the cylinders so their forward-facing sides turned in the same direction as the wind; this movement made air move faster across the front surface and slower behind, creating a pressure difference and pulling the ship forward....

By Naomi O’Leary L’AQUILA, Italy (Reuters) - Italy risks disaster if its schools are not strengthened against earthquakes, leading geologists said on Friday, in a call for action before the fifth anniversary of a quake in the university town of L’Aquila that killed over 300. Risk to life from earthquakes in Italy has worsened since the disaster on April 6, 2009, the National Council of Geologists warned at an event in the devastated city in the central Abruzzo region, saying buildings had continued to be constructed without respecting anti-earthquake regulations....

You can’t make money without money. That was the exciting and intuitively obvious idea behind microloans, which took off in the 1990s as a way of helping poor people out of poverty. Banks wouldn’t give them traditional loans, but small amounts would carry less risk and allow entrepreneurs to jump-start small businesses. Economist Muhammad Yunus and Bangladesh’s Grameen Bank figured out how to scale this innovation and won the 2006 Nobel Peace Prize for their work....

NASA’s well-traveled Voyager 1 is headed out of the heliosphere, the fluctuating bubble in space inflated by plasma streaming outward from the sun. For years Voyager 1 has been closing in on the heliopause—the outer edge of the heliosphere—where the solar wind meets the interstellar medium. Yet despite intriguing hints, the probe remains within the heliosphere, mission scientists announced last December. It appears that Voyager 1 has discovered another wrinkle in the structure of our local space environment, a kind of magnetic highway linking the heliosphere to what lies beyond....

1970 Sweet Suburbia “Massive movement from central cities to their suburbs, a population boom in the West and Southwest, and a lower rate of population growth in the 1960’s than in the 1950’s are the findings that stand out in the preliminary results of the 1970 Census as issued by the U.S. Bureau of the Census. The movement to the suburbs was pervasive. Its extent is indicated by the fact that 13 of the 25 largest cities lost population, whereas 24 of the 25 largest metropolitan areas gained....

Each night before “Greg” goes to bed he brushes and flosses his teeth. Then he double-checks the instructions on the dark brown bottle his nurse gave him before he unscrews the cap and tips five drops of a light-amber, oily liquid onto a spoon. The brew, glistening from the light of the bathroom fixture, is tasteless and has no odor he can detect. But it’s chock-full of bacteria. He sloshes the substance around in his mouth and swallows....

A deep question pervades the debates surrounding religion—whether God exists, sure, but that one is mighty difficult to answer. Instead we can ask a related, more approachable query: Why does God exist for some of us but not for others? Theologians and ministers preach that faith is preeminently a matter of personal choice. Is it, really? Not everyone is a believer, of course, nor do we all maintain allegiance to a single belief system throughout the course of our life....

Why does skin wrinkle with age? How can you slow or prevent this process? Suzan Obagi, assistant professor of dermatology at the University of Pittsburgh and director of the Cosmetic Surgery and Skin Health Center, offers this answer: Wrinkles arise from physical shifts that occur naturally as we grow older—and they are exacerbated by outside influences, such as exposure to sun or tobacco smoke. As we age, we gradually lose our collagen, a protein fiber that makes our skin firm; as a result, skin becomes thinner and more fragile....

Key Concepts Physics Heat Temperature Insulation Introduction How does a cooler keep things cold? Which material makes the best insulation? Try this project to find out how long you can keep an ice cube from melting once it’s out of the freezer! Background Have you used an insulated lunch box or bag to pack lunch for school or a cooler to pack food for a picnic? Why not just throw the food in a paper bag or plain box?...

Data visualizations using rainbow color scales are ubiquitous in many fields of science, depicting everything from ocean temperatures to brain activity to Martian topography. But cartographers have been arguing for decades the “Roy G. Biv” scale makes maps and other figures difficult to interpret, sometimes to the point of being misleading. And for the those with color blindness, they are completely unintelligible. Now scientists at a U.S. Department of Energy laboratory have developed a color scale that is mathematically optimized to be accurate for both color blind people and those with normal vision....

It’s not something NASA likes to advertise, but ever since its creation in 1958, the space agency has only conducted one direct, focused hunt for extraterrestrial life—and that was more than 40 years ago. It happened in 1976, when the twin Viking landers touched down at separate sites on Mars to look for any signs of life lurking on the planet’s desolate, freeze-dried surface. The Viking mission was—and still is—the most expensive planetary science mission ever launched as well as a technical tour de force that laid the foundations for all future interplanetary exploration....

Margie Peixoto was driving her pickup across her farm in the Brazilian state of Mato Grosso do Sul one February afternoon when she spotted some broken corn stalks and a trio of white-lipped peccaries (Tayassu pecari) ambling along the red-clay road as if they owned it. The moment these wild pig relatives spotted the truck, they snorted, snarled and disappeared into the head-high crop, where dozens more likely hid. “Every year the group gets bigger and bigger, and every year the damage to the crop is greater,” said Peixoto, a fit middle-aged woman from Zimbabwe, who met her Brazilian husband while traveling in Africa, and immigrated here to farm more than 30 years ago....

For me, there’s nothing particularly special about seeing a small Cessna take to the air. But watching an Airbus A380, the world’s largest commercial airliner, ascend is something altogether different. The way it lumbers into the sky just doesn’t seem real. Yet mechanical and aerodynamic adaptations make flight possible for such bulky craft. I imagine I would’ve had the same impression (and a dose of terror) watching a hulking pterosaur take wing, especially compared with the smaller feathered dinosaurs and birds that evolved later....