Posts

Greenhouse gas emissions are roaring back as coronavirus lockdowns lift, according to updated projections from the Global Carbon Project. Emissions in China have returned to 2019 levels—a sharp reversal from earlier this year when daily carbon dioxide levels in the country plunged by a quarter. In the United States, daily emissions were down by 7% in early June, compared with decreases of roughly a third in April. European and Indian emissions have followed similar patterns....

Key concepts Heart rate Exercising The heart Cardiovascular system Health Introduction As Valentine’s Day approaches, we’re increasingly confronted with “artistic” images of the heart. Real hearts hardly resemble to two-lobed shapes adorning cards and candy boxes this time of year. And the actual shape of the human heart is important for its function of supplying blood to the entire body. You have likely noticed that your heart beats more quickly when you exercise....

As cases of COVID-19 surge to record levels across the United States, national public health advisors Anthony Fauci and Deborah Birx have pushed for an approach that emphasizes intensive social distancing and widespread mask use, and many states are striving to slow the virus’s spread without resorting to complete lockdowns. That strategy helped some states mitigate their outbreaks through the summer. But with winter and major holidays coming, will such measures be enough?...

In 1946, an engineer was working near a piece of equipment known as a magnetron which is part of a radar system when he noticed that the radar emission at microwave frequencies melted the snack bar he had stashed in his pocket. Legends disagree as to whether it was a peanut cluster bar or a chocolate one, but the fact remains that rather than just mourning the loss of his snack, he did a little investigating....

Editor’s Note (8/30/16): This story was updated at 3:30 P.M. Sit! Stay! Good boy! Many of us use such words with our nonhuman best friends every day. Now new research suggests that they may actually understand at least some of what we say—and that they may be paying a lot of attention to how we say it. The findings, published this week in Science, may prove what pooch-lovers have long believed to be true: Their beloved canines can process language in a more nuanced way than has long been assumed....

The riot of colors that erupts on trees each fall drives billions of dollars in tourism and remains a key way for people to connect with nature. But that simple transition from summer’s lush greens to fall’s brilliant reds, oranges and yellows can be impacted in surprisingly complex ways by weather and climate, and those effects may be even more pronounced in the decades to come. This year, drought across New England and the Southeast has led to the earlier appearance of color in some areas, but later in others, depending on factors like the severity of the drought and the particular species of trees affected....

When it comes to your love life, the impact of your diet could go beyond having a few extra pounds around the waist—what you eat may also influence how pleasing your body smells to members of the opposite sex. Scientists have long observed such a link in animal research—female salamanders are attracted to males that eat nutrient-rich diets, for example—and something similar may be true in humans, some preliminary studies suggest....

All of us, not just astronomers, have an obvious fascination with what happens when matter gets sucked into the maw of a black hole. Usually, we’ve had to watch from the equivalent of partial-view bleacher seats as these cosmic garbage disposals do their thing in the Milky Way and in distant galaxies. For once, though, we may have procured primo seats behind the dugout. In the next few years, the supermassive black hole at our galaxy’s center could shred and consume a cloud of dust and gas with the mass of a small planet....

Pres. Barack Obama’s promise last week that the U.S. would respond “at a time and place of our choosing” to Russia’s alleged tampering in the recent presidential election resembles the White House’s cyber saber rattling of a few months ago, but some security experts think it is time to walk the walk. “The main difference between earlier threats and the latest is that people think he might actually do something this time,” says James Lewis, senior vice president and director of the Center for Strategic & International Studies’ (CSIS) Strategic Technologies Program....

A molecule of DNA, holding its blueprint for life, is about 2.5 billionths of a meter in diameter. Scientists now have the ability to push and pull and build molecules of that size, as well as to create devices that sense them with unprecedented precision. These skills, gained through painstaking work during the past decade, are leading to new medicines and ways of diagnosing disease. In this special report, Scientific American examines what nanomedicine is bringing us now, what is coming soon and what the future will likely hold....

Anyone who follows environmental issues on Capitol Hill has likely seen them—groups of women in bright-red T-shirts with small kids in tow. These are the volunteers of Moms Clean Air Force, and they’re pushing lawmakers to consider how U.S. EPA’s actions will affect families. The “supermoms” have become a frequent presence in Washington, D.C., in large part thanks to the efforts of the group’s co-founder and senior director, Dominique Browning. The 62-year-old mother started the group in 2011 with two Environmental Defense Fund board members to push for a systemic shift in how the country approaches climate change....

Pres. Barack Obama has proposed that both the U.S. and Russia continue to deplete their nuclear weapons reserves, encouraging a one-third reduction to arsenal sizes. His June 19 proposal, which did not yet specify a time line for destruction of the weapons reduction, expands on the 2010 New START Treaty between Russia and the U.S., which calls for each country to possess no more than 1,550 warheads by 2018. Efforts to cut stockpiles and thus decrease the risk of accidental nuclear detonations and launches have so far been hampered by risks posed by the verification process....

Grid City is a small planned city laid out on a completely regular six-by-five grid with streets going north-south and east-west. There is one building per city block. Grid occasionally suffers major snowstorms. The Grid City Snow Clearing Department (GridClear) wishes to make it possible for residents to move about on paved roads but the effort to move the snow is so great that they want to minimize plowing as well as danger to the public....

As billions of dollars pour into quantum computing and countries build communication networks secured by quantum encryption, the prominence of quantum information science has become increasingly hard to ignore. This year’s Breakthrough Prize in Fundamental Physics honors four pioneers who combined math, computer science and physics to do “foundational work in the field of quantum information.” The prize is shared between Charles Bennett of IBM, Gilles Brassard of the University of Montreal, David Deutsch of the University of Oxford and Peter Shor of the Massachusetts Institute of Technology....

A round of high fives after a successful sales call this month could be the start of something big: big numbers of salespeople calling in sick with the flu, passed from palm to palm to nose. In a restaurant break room, a sneeze from one employee can trigger weeks of sniffles and fever among co-workers. These daily run-ins on the job sideline a lot of us, particularly at this time of year....

Fuel economy is hardly the most popular subject among teenagers, but it’s a passion for 17-year-old Jonny Cohen, who’s found a way to save schools money and reduce greenhouse gas emissions by increasing school bus fuel efficiency. The idea popped into his head on a walk home from school when he was 12. The then-seventh-grader was taking summer classes on aerodynamics at Northwestern University, and it dawned on him there must be a way to streamline the bulky, boxy shape of school buses....

Our concepts of how the two and a half pounds of flabby flesh between our ears accomplish learning date to Ivan Pavlov’s classic experiments, where he found that dogs could learn to salivate at the sound of a bell. In 1949 psychologist Donald Hebb adapted Pavlov’s “associative learning rule” to explain how brain cells might acquire knowledge. Hebb proposed that when two neurons fire together, sending off impulses simultaneously, the connections between them—the synapses—grow stronger....

Take a moment to name as many geniuses as you can. How many of them are men? There is something about the way we view such extraordinary thinkers that has excluded all of them who happen to be women. In a new book, journalist Janice Kaplan sets out to correct the record. The Genius of Women is a collection of stories but also a call to let go of old biases....

The first decade of the HIV epidemic was a gruesome horror show of human bodies wasting away. Then, miraculously, succeeding waves of new drugs added flesh to withered bodies that arose like Lazarus from the near dead. HIV infection quickly became a treatable, manageable chronic disease. HIV prevention, on the other hand, has been a far slower, incremental and less successful endeavor. The most recent step of progress is something called a dapivirine ring....

Imagine a planet where jellyfish rule the seas, giant rodents roam the mountains and swarms of insects blur everything in sight. It may sound far-fetched, but enough global warming is likely to change the distribution of wildlife on Earth. While species that are under threat, such as the polar bear, seem to get all the attention, others are beginning to thrive like never before. In the past three months, new studies have been published about killer whales, wandering albatross and trumpeter swans—all of which appear to be benefiting from climate change....