For many people around the world, a subway journey means speeding from one dull station to the next, surrounded by too many uncomfortable, impatient people. But on the Moscow Metro, taking the subway is like walking through a national heritage site. Depending on where you get off, you'll receive a brief course in architectural movements and face colorful glass windows, marble(大理石) columns, gilded(鎏金的) mosaics and painted scenes from Russian history.

    “These extraordinarily beautiful places are unlike any metro station I've ever seen, “says Vancouver-based photographer David Burdeny.

    When Burdeny, who himself has a master's degree in architecture, first found out about Moscow's metro stations, he was struck by the work of art. In all, he has photographed 20 of the most beautiful stations.

    Burdeny had originally planned to focus on Russian stations more generally, taking photos of examples in both St. Petersburg and Moscow.

    “But when I saw the stations in Moscow, they just completely blew away the St. Petersburg ones,” he says.

    Shooting in the subway sounds simple, but it is not without challenges. For one thing, Burdeny had to figure out a way to access them between 00:30 a.m. and 5:30 a.m., when the stations were closed.

    In the end, he settled on Arbatskaya Metro Station, whose vaulted(拱状的) arches he found the most beautiful. But it also represented a challenge he was not sure if he was able to overcome: conveying the hugeness of the spaces. The Arbatskaya platform, for example, stretches 820 feet.

    “Some of the arches are quite long,” he says. “When you enter them, they're just so completely grand.”

    Amazon is breaking into physical retail(零售) in a new way. The online retail giant revealed a new kind of physical store concept in a video published on Monday.

    The store, called Amazon Go, doesn't work like a typical Walmart or supermarket. Instead, it's designed so that shoppers will use an app, also called Amazon Go, to automatically add the products that they plan to buy to a digital shopping cart by scanning a QR code. They can then walk out of the building without waiting in a checkout line because Amazon will charge their Amazon account and send them a receipt(收据).

    The first Amazon Go store is located in Seattle, where Amazon is headquartered. For years, there have been rumors the e­commerce company would expand its dominance(主导地位) from digital to physical shopping. Amazon began experimenting with physical bookstores a year ago, but Amazon Go may mark its boldest(大胆的) bet on physical ones yet. By removing much of the staff needed to operate a store, Amazon keeps costs lower than traditional competitors. It's also in a strong position to bring together data on its customers' shopping habits online and offline to make better suggestions in all situations.

    However, the company could be thought of as being a threat to some of the 3.4 million Americans who work as cashiers, according to the Bureau of Labor Statistics. And Donald Trump repeatedly criticized Amazon and its founder Jeff Bezos, “He's using the Washington Post for power so that the politicians in Washington don't tax Amazon like they should be taxed.”

    “Four years ago we asked ourselves: what if we could create a shopping experience with no lines and no checkout? Could we push the boundaries of computer vision and machine learning to create a store where customers could simply take what they want and go?” The company says on an informational page about Amazon Go. For now, Amazon is starting slow. The Amazon Go is only open to Amazon employees in our Beta program, and is scheduled to open to the public in 2017.

    Since my retirement (退休) from teaching music in 2001, I have spent a good deal of time painting as an artist. I actually began drawing again in the summer of 1995 when my father died, so perhaps I was trying to recover from the loss of my father, or maybe it was just that it brought back memories of him. In any case, I drew pen and ink animals and landscapes much influenced by Krenkel and St. John for five years.

    For some strange reason, I had been waiting until my retirement to start doing watercolors again, but as soon as I walked out of the school door for the last time I picked up my brushes and rediscovered Andrew Wyeth, who quickly became my favorite artist. I had looked through all the art books I had on my shelves and found his watercolors to be the closest to how I thought good watercolors should look. So I painted landscapes around Minnesota for three years and tried out many other types of painting. However, watercolors remained my first choice, and I think I did my best work there, showing my paintings at a number of art exhibitions.

    Art is now together with my piano playing and reading. There is a time for everything in my world, and it is wonderful to have some time doing what I want to do. As Confucius once said，“At seventy I can follow my heart's desire (渴望).”

    Dogs were living as companions to the early settlers of North America over 10,000 years ago. The oldest domestic dogs in the Americas were thought to be around 9500 years old. Angela Perri of Durham University, UK, and her colleagues have carried out fresh radiocarbon dating on the two dog skeletons that gave this date, discovered in the prehistoric Koster site in Illinois, and found they were even older: around 10,100 years old.

    A third dog from another Illinois site called Stilwell II was older still, at 10,190 years old. That makes it the oldest known domesticated dog in the Americas. The team concluded that all three dogs were domesticated as they skeletons were complete and unskinned, and so hadn't been butchered for food. They had also been carefully buried, evidence they were valued by their owners. The Stilwell II dog, which probably resembled a small English settler, was under what seemed to be the floor of a living area. It is unclear why it took so long for tame dogs to arrive in the Americas, given that they were domesticated at least 14,000 years ago in Eurasia. By this time, people were already moving into North America from Siberia; there is evidence some reached Chile 18,500 years ago. Geneticists have found signs of at least three waves of migration over the following millennia. There is no evidence that domestic dogs accompanied them. “We don't know if dogs were part of the first waves of immigration to the Americas" says Luc Janssens of Ghent University in Belgium. "It could be so, but no archaeological bones have yet been found." It is "overwhelmingly probable" that some of the early settlers did bring dogs to the Americas, but they may not have had "the time or the spiritual compulsion to bury them", says Pat Shipman of Pennsylvania State University.

Help Hermit Crabs

    Hermit crabs are nature's recyclers. They eat waste and help keep oceans and shores clean. Unlike other crabs, the hermit crab has a thin outer shell over its soft tail. This makes the hermit crab easy prey for hungry predators(天敌).Hermit crabs stay safe by living in old seashells. A hermit crab is picky(狡猾); it tries on many shells until it finds one that fits just right. In recent years, however, many hermit crabs have had trouble finding their perfect homes. What is the problems. There are not enough shells to go around!

    One reason for the seashell shortage is that ocean water is not as clean as it once was. This has caused chemical changes to sea water. Some sea animals, like snails, are affected by these changes.  Now there are fewer snails making shells. People visiting the beach often take shells home as souvenirs(纪念品).This is another problem. Other people even take shells for their own pet hermit crabs! They do not realize that hermit crabs in the wild need those shells too.

    Now people are working to solve this hermit crab housing shortage. They are teaching beach-Boers to leave seashells where they belong--at the seashore! Some people even make fake seashells that they hope the hermit crabs will like. For example, a group called Project Shelter invited people who visited their website to create different designs for hermit crab shells.

    These designers had a lot to consider. What kind of material should be used to build a seashells. The material must be light enough for the hermit crab to carry, but strong enough to protect the crab from predators. The man-made shells could not contain glue or any other substance(物质)that might harm a hermit crab. Another challenge with building a hermit crab home was the opening to the shell. Too big would mean the crab would not feel safe. Too small would be uncomfortable, and the crab would not want to move in.

    The Project Shelter shells are placed in the wild for hermit crabs to find. Lucky hermit crabs can move into these new dream homes.

Research has found that using wood for construction instead of concrete and steel can reduce emissions. But Tim Searchinger at Princeton University says many of these studies are based on the false foundation that harvesting wood is carbon neutral (碳中和). "Only a small percentage of the wood gets into a timber (木料) product, and a part of that gets into a timber product that can replace concrete and steel in a building," he says. Efficiencies vary in different countries, but large amounts of a harvested tree are left to be divided into parts, used in short-lived products like paper or burned for energy, all of which generate emissions.

In a report for the World Resources Institute, Searchinger and his colleagues have modelled how using more wood for construction would affect emissions between 2010 and 2050, accounting for the emissions from harvesting the wood. They considered various types of forests and parts of wood going towards construction. They also factored in the emissions savings from replacing concrete and steel.

Under some circumstances, the researchers found significant emissions reductions. But each case required what they considered an unrealistically high portion of the wood going towards construction, as well as rapid growth only seen in warmer places, like Brazil. In general, they found a large increase in global demand for wood would probably lead to rising emissions for decades. Accounting for emissions in this way, the researchers reported in a related paper that increasing forest harvests between 2010 and 2050 would add emissions equal to roughly 10 percent of total annual emissions.

Ali Amiri at Aalto University in Finland says the report's conclusions about emissions from rising demand are probably correct, but the story is different for wood we already harvest. "Boosting the efficiency of current harvests and using more wood for longer-lived purposes than paper would cut emissions," he says. "We cannot just say we should stop using wood."