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A suite of experiments that use the gene-editing tool CRISPR–Cas9 to modify human embryos have revealed how the process can make large, unwanted changes to the genome at or near the target site. The studies were published this month on the preprint server bioRxiv, and have not yet been peer-reviewed. But taken together, they give scientists a good look at what some say is an underappreciated risk of CRISPR–Cas9 editing. Previous experiments have revealed that the tool can make ‘off target’ gene mutations far from the target site, but the nearby changes identified in the latest studies can be missed by standard assessment methods....

Although most of us don’t know it, humans emit hundreds of odor compounds that waft into the air around us. As our bodies change with age, disease and reproductive status, this cloud of volatile chemicals changes, too. What we sweat, secrete and exhale documents the ever-changing landscape inside of us. As far back as 400 B.C., Hippocrates took note of how some of these odors, especially in urine, reflected disease. But the human olfactory sense—even that of Hippocrates—has nothing on the capacity of the canine nose for detecting smells....

The National Climate Assessment wasn’t the only global warming report the Trump administration quietly released over the Thanksgiving holiday. The U.S. Geological Survey reported Friday that about one-quarter of all U.S. carbon emissions come from fossil fuels extracted from public lands. Environmentalists reacted by renewing calls to end leasing for oil, gas and coal leasing on federal tracts. Between 2005 and 2014, an average of 23.7 percent of American carbon dioxide emissions came from energy produced on public lands....

The foundation of a Russian billionaire announced Tuesday (Dec. 11) that it would hand out two $3-million physics prizes — one to legendary cosmologist Stephen Hawking and the other to group of CERN scientists who spearheaded this year’s discovery of a Higgs-like particle at the world’s largest atom smasher, the Large Hadron Collider (LHC), in Geneva. The Fundamental Physics Prize, nearly three times as lucrative as the Nobel Prize, was founded last year by physicist-turned-entrepreneur Yuri Milner and stands as world’s richest science award....

“You scratch my back, I’ll scratch yours,” we say, and “An eye for an eye, a tooth for a tooth.” Conventional wisdom and decades of research point to the universal human tendency to reciprocate, responding to good or bad acts in kind. But if people only give as good as they get, how do conflicts escalate? The answer, according to recent University of Chicago research, is that positive and negative reciprocity are not symmetrical: we retaliate against selfishness more than we reward generosity—even when the slights are only illusory....

Full question: How did they ever find the chemical that makes your pupils dilate? Was it a beautifying technique in Victorian times (or in the past 200 years)? Donald Mutti, a professor at Ohio State University’s College of Optometry, eyes an answer to this query. Our pupils naturally dilate in darkness and constrict in bright lights through the actions of two opposing muscles in the iris, the iris dilator and sphincter....

It’s an Olympics year, which means that Lee Sweeney’s phone is ringing off the hook. Athletes call him three or four times a day asking for help, offering him money. They’re persistent, practically begging, but he always says no. After all, Sweeney is not an athletic coach; he is a soft-spoken physiologist at the University of Pennsylvania School of Medicine, and he is developing treatments that could stop age-related muscle decline....

For 20 years Joan* quietly suffered from an unrelenting desire to commit suicide. She held down a job as a special-education teacher and helped care for her family in the northeastern U.S. Yet day after day she struggled through a crushing depression and felt neither joy nor pleasure. Except for the stream of psychiatrists recommending different antidepression treatments—all of which failed to provide relief—Joan kept her condition private. She says it was the fear of hurting her students or abandoning her father that kept her alive....

From Ensia (find the original story here); reprinted with permission. July 19, 2016 — Ten miles south of Tel Aviv, I stand on a catwalk over two concrete reservoirs the size of football fields and watch water pour into them from a massive pipe emerging from the sand. The pipe is so large I could walk through it standing upright, were it not full of Mediterranean seawater pumped from an intake a mile offshore....

EaglePicher Technologies, a manufacturer of specialized batteries for military and space programs, is partnered with the federal government to develop a powerful battery storage technology to help utilities smooth out the ups and downs of renewable power. It’s a familiar path for the Joplin, Mo., company. EaglePicher began developing a battery for space applications in the mid-1980s that used sodium and sulfur components. Its model performed successfully on the Columbia space shuttle in 1997....

Tucking a spreadsheet in among the toiletries in the bathroom cabinet might seem a bit odd, but for 76-year-old Barbara Pines, it is the easiest way to keep track of all the prescription medications, over-the-counter pills and supplements that she and her husband take. The document lists 20 drugs—along with the strength, number of times taken and purpose. “I print this schedule and take it to any new doctor we go to,” she says....

In these days of hybrid cars and carbon credits, it is common knowledge that substances exhaled by autos and coal plants are harmful to our respiratory system. What may be surprising is the degree to which they may harm the brain—in some instances, as much as exposure to lead. A recent string of studies from all over the world suggests that common air pollutants such as black carbon, particulate matter and ozone can negatively affect vocabulary, reaction times and even overall intelligence....

Oof. It was yet another “gotcha” moment for me working here at Scientific American Mind. Walking home from the train a few days ago, I was running through my mental to-do list. I realized that, yet again, I somehow had not gotten around to the simple task of making appointments for routine dental and physical checkups. Fact is I still haven’t done so even as I type these words. Why do I do that, when it’s so obviously smarter to get a quick screening now rather than risking the bother and expense of treating a possible cavity later?...

If you believe budtender wisdom, consuming a strain called Bubba Kush should leave you ravenous and relaxed whereas dank Hippie Chicken should uplift you like a dreamy cup of coffee. But if you take pure, isolated delta-9-tetrahydrocannabinol, or THC—the main psychoactive ingredient in marijuana—you’ll experience “a high that has no specific character, so that seems boring,” says Mowgli Holmes, a geneticist and founder of a cannabis genetics company Phylos Bioscience. What gives cannabis “character,” in Holmes’s view, are the hundreds of other chemicals it contains....

We humans are swamped with text. It’s not just news and other timely information: Regular people are drowning in legal documents. The problem is so bad we mostly ignore it. Every time a person uses a store’s loyalty rewards card or connects to an online service, his or her activities are governed by the equivalent of hundreds of pages of legalese. Most people pay no attention to these massive documents, often labeled “terms of service,” “user agreement” or “privacy policy....

A new method for detecting exposure to ionizing radiation could quickly reveal those most at risk in the event of a “dirty bombing” or nuclear incident, say researchers at the Duke University Medical Center in Durham, N.C. Reporting in this week’s issue of PLoS Medicine, the Duke team suggests that drawing a blood sample and then using gene-chip technology to scan thousands of genes in the DNA of lymphocytes (white blood cells found in the blood, gut and bone marrow) could rapidly determine whether someone requires treatment for radiation poisoning....

Editor’s note (10/9/2012): We are making the text of this article freely available for 30 days because the author, Sir John B. Gurdon, is one of the winners of the 2012 Nobel Prize in Physiology or Medicine. The full article with images, which was published in the December 1968 issue, is available for institutional users only at this time (pdf). The means by which cells first come to differ from one another during animal development has interested humans for nearly 2,000 years, and it still constitutes one of the major unsolved problems of biology....

From the tallest peak in Hawaii to a high plateau in the Andes, some of the biggest telescopes on Earth will point towards a faint smudge of light over the next few weeks. The same patch of sky will draw the attention of Gennady Borisov, an amateur astronomer in Crimea, and many other hobbyists who will sacrifice proper sleep and doze through their day jobs rather than miss this golden opportunity....

Chemists in Italy have proposed a reason why sulfate-rich lead chromate dyes, used widely in paintings, degrade under light. Lead chromate dyes were a staple tool that Vincent van Gogh used widely in his art, including his iconic Sunflowers paintings. He enjoyed mixing pigments to obtain rich, striking colours but his favoured sulfate-rich dye, a mixture of yellow lead chromate and white lead sulfate, has been known to degrade under sunlight, fading the once vivid yellow of his Sunflowers series into duller paintings....

The searing “megadrought” that has gripped the southwest U.S. for more than two decades is the driest 22-year period in at least 1,200 years. The region hasn’t seen a more severe drought since the start of the scientific record around the year 800, according to new research published yesterday. An exceptionally dry year in 2021 helped break the record. Before last year, a previous megadrought occurring in the late 1500s was the only other drought known to be worse than today....