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Beyond its color, there’s often a beautiful symmetry or pattern to hair–the way individual strands fall at angles in-line with their neighbors. This ordering is too precise to be left up to randomness, says a team of researchers, who reveal in this week’s issue of Proceedings of the National Academy of Sciences that hair grows in a refined two-part process. In 2004 a group of researchers led by Jeremy Nathans, a geneticist and molecular biologist at the Johns Hopkins School of Medicine, discovered that mutant mice, missing a gene that codes for the protein frizzled 6, had unruly waves and tufts of hair rather than neatly ordered pelts....

The hunt for the fountain of youth is back to square one—at least for those seeking it in blood. New findings cast doubt on research that attempted to explain why the muscles of an old animal can be rejuvenated with a dose of blood from a young animal. For decades, scientists have sought to understand the anti-ageing effects of parabiosis, a technique in which researchers sew a young mouse and an old mouse together so that they share a circulatory system....

Lack of compliance often leads to worsening chronic conditions and excess hospitalization. Studies consistently show one third to one half (pdf) of all U.S. patients do not take their medicines as directed, and this ends up costing the health care system between $100 billion and $300 billion annually. People fail to follow drug regimens for reasons as complex as the health care system itself. Drugs can remind people they are “sick” or generate new, unpleasant side effects....

Antibiotic resistance, which transforms ordinary microbes into menaces that cannot be easily controlled, is exacting a growing toll on the human population. More than two million people in the U.S. develop drug-resistant infections each year and at least 23,000 of them die as a result. Yet most antibiotic resistant infections are only identified long after a patient has left the doctor’s office. The diagnostic hitch is how long it takes for bacteria to grow in the laboratory....

As wildfires ravage Australia’s land and forests, so far killing an estimated one billion terrestrial animals, researchers worry marine and freshwater species will become invisible victims. More than 17.1 million hectares of land have burned across the country, with the worst fires currently raging in New South Wales and Victoria, states in the nation’s southeast, according to Australia’s Department of the Environment and Energy (DEE). Adrian Meder, a marine campaigner at the Australian Marine Conservation Society (AMCS), says these fires are leaving behind a huge number of charred plants and a massive amount of ash....

City dwellers may be familiar with flies and cockroaches, but a closer look shows there is a mind-blowing array of tiny critters that creep and crawl through the landscape. Because of COVID-19, this past summer, the biodiversity discovery group Taxon Expeditions, based in Leiden, the Netherlands, decided to forego a faraway research trip to tropical rain forests or caves in the Balkans. Instead its investigators stayed closer to home, focusing their magnifying lenses inside Amsterdam’s city limits....

On winter nights, New Delhi burns with innumerable fires. Flames flicker along pavements and street corners, where the destitute huddle to stay warm and cook their suppers, while night watchmen stand guard next to their own small blazes outside private homes. The rising plumes of smoke mingle with exhaust and dust stirred up by overloaded trucks that rumble down roads blanketed in fog. The mixture melds into a nearly opaque substance that leaves a metallic taste on the tongue....

Australia’s vast outback stores 9.7 billion metric tons of carbon, but has the capacity to double those holdings by 2050, according to a report released yesterday. The vast region, which covers roughly 2.5 million square miles in Australia’s interior, could sequester another 1.3 billion metric tons of carbon by 2050, concludes the analysis, sponsored by the Pew Environment Group and the Nature Conservancy. The groups argue it would be a cost-effective approach to reducing Australia’s net contribution to climate change, the equivalent of reducing the country’s emissions 5 percent by 2030, assuming a business-as-usual emissions scenario....

The reasons behind why people are gay, straight or bisexual have long been a source of public fascination. Indeed, research on the topic of sexual orientation offers a powerful window into understanding human sexuality. The Archives of Sexual Behavior recently published a special section devoted to research in this area, entitled “The Puzzle of Sexual Orientation.” One study, conducted by scientists at the University of Lethbridge in Alberta, offers compelling, cross-cultural evidence that common genetic factors underlie same-sex, sexual preference in men....

Even after decades of searching, scientists have never seen a particle of dark matter. Evidence for the substance’s existence is close to incontrovertible, but no one yet knows what it is made of. For decades physicists have hoped dark matter would prove to be heavy—consisting of so-called weakly interacting massive particles (WIMPs) that could be straightforwardly detected in the lab. With no definitive sign of WIMPs emerging from years of careful searching, however, physicists have been broadening the scope of their quest....

Biologists have long been studying genes to understand the history of branching on the tree of life, which unites all living creatures on earth—be they marmosets or microbes. One leaf on this sprawling ancestral tree, nestled among the apes, is Homo sapiens. Each individual in our species is an assemblage of cells, which cooperate to generate our body. Normally the cells obey a covenant, established by trial and error more than 600 million years ago, in the first forms of multicellular life....

One in nine Americans aged 65 and older has Alzheimer’s disease, a fatal brain disorder with no cure or effective treatment. Therapy could come in the form of new drugs, but some experts suspect drug trials have failed so far because compounds were tested too late in the disease’s progression. By the time people show signs of dementia, their brains have lost neurons. No therapy can revive dead cells, and little can be done to create new ones....

The vast Greenland ice sheet is melting at some of its fastest rates in the past 12,000 years. And it could quadruple over the next 80 years if greenhouse gas emissions don’t decline dramatically in the coming decades. Research published yesterday in the journal Nature warns that the ice sheet’s future losses depend heavily on how quickly humans cut carbon emissions today. Led by Jason Briner of the University at Buffalo, State University of New York, the study is among the first to compare the possible future of the ice sheet with its ancient past....

When I was in high school, I learned one day about the density of curves in an introductory course on calculus. A simple pair of differential equations that model the interactions of predators and prey can give rise to an infinite number of closed curves—picture concentric circles, one nested within another, like a bull’s-eye. What is more, the density of these curves varies depending on their location. This last fact seemed so strange to me....

Scientific American presents Savvy Psychologist by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies. A full 40% of Americans don’t like to fly. It makes sense if you think about it: hurtling across time zones in a metal tube at the height of Everest isn’t something our ancestors evolved to face. We get by on white knuckles, a Xanax, or a pre-flight pit stop at the terminal bar....

When you suspect a fever, you pop a thermometer in your mouth and take your temperature. In diseases such as Alzheimer’s and Parkinson’s, no simple tool can identify its biological traces. Now hope is emerging from an unexpected source: lasers. A new study suggests that a laser technique thought to be safe in humans can identify the telltale protein clumps that accumulate in these disorders. Amyloid fibrils, which are dense buildups of abnormally folded proteins, occur in many neurological diseases....

It’s now been more than two months since NASA’s long-lived Opportunity Mars rover last phoned home. Opportunity hasn’t made a peep since June 10, when dust in the Red Planet’s air got so thick that the solar-powered rover couldn’t recharge its batteries. Opportunity’s handlers think the six-wheeled robot has put itself into a sort of hibernation, and they still hope to get a ping once the dust storm has petered out....

What was the inspiration for the book? It got started when I noticed a paradox in the lives of some really creative people: people like Charles Darwin, Stephen King, Maya Angelou, who are obsessed with their work. But when you look at how many hours a day they spent working, it’s a surprisingly small number. For someone living in Silicon Valley and growing up in an era that assumes overwork is the norm, the idea that you could go in the opposite direction and yet still do really amazing stuff was really compelling....

A rudimentary quantum computer has rediscovered the Higgs boson. Sort of. Physicists have been working hard to develop machines that can use quantum mechanical tricks to speed up computation. But they also hope that such quantum computers can return the favour and help them to discover new laws of nature. Now, a team has shown that a quantum circuit can learn to sift through reams of data from atom-smashing experiments in search of a new particle....

Around one billion people live in extreme poverty, suffering from economic deprivation so severe that they must struggle daily for survival. Extreme poverty is sometimes defined as living on under $1 a day, but more accurately it is the lack of reliable access to basic needs, including adequate food, basic health services, safe drinking water and connectivity with the wider world (via roads, power and telecommunications). Recent orthodoxy holds that extreme poverty results from corruption, mismanagement and weak institutions....