Science

The sun is blazing down when I meet endangered Galápagos tortoises for the first time. They look like modern-day dinosaurs, lazily ambling around on scaly, dusty bowlegs. I proffer a carrot to the largest of the three—a 300-pound female—who grabs it with strong, beaklike jaws, neatly splitting it in two. After consuming it she extends her long neck forward, inviting me to gently rub her under the chin. This intimate encounter takes place nowhere near the wild deserts of the Galápagos Islands—I’m more than 3,000 miles away, in a white-fenced suburban backyard in Long Island, N.Y. The three tortoises crawling around me—“Peewee,” “Maxine” and “Tony”—belong to Michael Soupios, a smiling, bespectacled 67-year-old graduate adviser and professor of political science at Long Island University Post. Soupios has spent years studying Galápagos tortoises, and easily rattles off facts about their history in the wild—from past and present population figures to the latest efforts by scientists and nonprofit …

A complex cascade of biochemical signals determines what we eat, when we eat and how much we eat. Our digestive tracts and fat cells are known to secrete hormones that drive our hunger levels and our sense of satisfaction after eating. Now a new player has come to the table, our bones. A paper published this March in Nature shows bone cells secrete a hormone called lipocalin 2—and it has a surprising effect in mouse experiments of reducing appetite and stabilizing blood sugar independently of other hormones Stavroula Kousteni, a physiologist at Columbia University College of Physicians and Surgeons, and her colleagues showed 90 percent of the hormone lipocalin 2 was produced by osteoblasts, bone cells that create the chemicals necessary to build new bone. Because of its chemical structure scientists previously thought fat cells made the hormone. Lipocalin 2 is released after eating and reaches peak levels about an hour after a meal. When …

This Earth Day scientists and their advocates will march in the streets to support scientific research and protest antiscience policies. More than 500 demonstrations are planned for Saturday in communities around the world—from Washington, D.C., to Tokyo to Accra, Ghana. The event, called the March for Science, is not just a one-off effort though. Its organizers say they have plans to create a lasting movement, one that will help connect people of all political beliefs to scientists and their work—and that will also push the public to demand science-based policies from the government. Although it is unusual for researchers to get involved in such vocal advocacy—something the march’s organizers have faced criticism for—those participating feel it is a necessary step to defend science. As the march’s mission statement explains, “People who value science have remained silent for far too long in the face of policies that ignore scientific evidence and endanger both human life and …

An injection of “new blood” is a phrase long used as a metaphor for the revitalizing effect of fresh minds on a stagnant organization. But research now suggests it also applies in a literal sense. In a development that calls to mind both vampire lore and stories of bathing in blood, young blood appears to in fact rejuvenate old brains. Researchers at Stanford University led by neuroscientist Tony Wyss-Coray showed in a 2014 study that infusions of blood from young mice reversed cognitive and neurological impairments seen in old ones. They used a somewhat bizarre technique in which two mice were sutured together in such as way that they shared a circulatory system (known as parabiosis), and found old mice joined to their youthful counterparts showed changes in gene activity in a brain region called the hippocampus as well as increased neural connections and enhanced “synaptic plasticity”—a mechanism believed to underlie learning and memory in …

Coming together: simulation uses LIGO data to explain black hole binaries In February 2016, researchers at the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) in the US announced a ground-breaking discovery – on 14 September 2015 they had made the first ever direct detection of gravitational waves. After decades of trying to observe these ripples in space–time, the scientists had at last addressed the final unverified prediction of Einstein’s general theory of relativity. Success was quickly followed by success and a few months later a second detection was reported. In both cases (called GW150914 and GW151216 respectively), as well as a less statistically significant event (LVT151012), the gravitational waves were produced by two stellar-mass black holes in a binary orbit that merged to form one larger black hole. While the detection events are a significant breakthrough, they are still shrouded in mystery. “Previous to this, we never observed a black hole binary system, which leads to …

It has been 20 years since Bill and Melinda Gates first started using their fortune to address global health issues. By focusing on the diseases that hit the poorest parts of the world the hardest, their foundation has since saved countless lives and prevented untold suffering. “My enthusiasm and belief that this is the right way for this money to be spent is as strong as it was then,” Bill Gates said in a telephone interview with Scientific American before attending a major international health meeting this week in Geneva. But he acknowledged that making progress has not been as simple a process as he at first assumed. “Some of the naiveté that I had then was that if we created new tools [to identify and treat these diseases] that actually getting them out to people would be fairly straightforward,” Gates says. “And although I was also naive about some of the [drug] discovery stuff …

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. These include THC’s cousin cannabinoids such as cannabidiol, along with other compounds called terpenes and flavonoids. Whereas terpenes are generally credited with giving pot its varied fragrances—limonene, for example, imparts a snappy, citrusy perfume—the cannabis industry and some researchers have espoused the controversial idea that such compounds can enhance or alter THC’s psychoactive and medicinal properties. This so-called “entourage effect” refers to this scrum of compounds supposedly working in concert …

We humans are social animals. Most of us interact with others on a daily basis, and form complex social groups containing dozens of friends, relatives and peers. Maintaining such a network involves tracking our own relationships to individuals within it, and also requires some understanding of their relationships to one another. With such knowledge, we can quickly figure out another person’s social standing and, with that, infer how best to behave toward them. But what happens in the brain during this process? Research published today in Nature Human Behavior shows seeing familiar people activates a network of brain regions that appears to encode their position within the social group. Carolyn Parkinson of the University of California, Los Angeles, and her colleagues from Dartmouth College recruited 275 first-year MBA students and asked them to complete an online survey that included questions about which classmates they like to spend their free time with, who they visit at …

Habitable zone: artist’s impression of LHS 1140b An exoplanet orbiting a nearby red-dwarf star may be the “best place to look for signs of life beyond the solar system”, according to the team of astronomers that has discovered the rocky world. The exoplanet is called LHS 1140b and is located just 39 light-years from Earth. It has a density that suggests that it has a rocky surface with iron core. LHS 1140b is also in the habitable zone of its star and the astronomers say that it could have an atmosphere. The new exoplanet orbits LHS 1140, which is a faint red dwarf that is much smaller and cooler than the Sun. LHS 1140b was discovered by a team led by Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics. The researchers used the MEarth facility in Arizona to detect dips in the starlight from LHS 1140, which occur when the exoplanet passes between the star and Earth. Then the European Southern Observatory’s …

For scientists searching the skies for other Earth-like planets—other living worlds—the brightest hope may be a quiet star too dim to be seen with the naked eye, a sedate and solitary red dwarf called LHS 1140 nestled just 40 light-years away in the southern constellation of Cetus. There an international team of astronomers has found a world that, while not a twin of Earth, certainly counts as a close cousin. LHS 1140b is a “super-Earth,” a planet bigger than ours but smaller than Neptune, and the most common variety of world thought to exist in our galaxy. Many erstwhile super-Earths, however, have proved to be uninhabitable “mini-Neptunes” smothered beneath thick layers of gas. This world is different. At just under 50 percent larger than Earth but more than six times as heavy, its dimensions suggest it must be a ball of rock and metal, potentially with a thin and comparatively Earth-like atmosphere. Its 25-day orbit …

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