Computers have beaten human world champions at chess and, earlier this year, the board game Go. So far, though, they have struggled at the card table. So we challenged one AI to a game.

    Why is poker(扑克) so difficult? Chess and Go are “information complete” games where all players can see all the relevant information. In poker, other players' cards are hidden, making it an “information incomplete” game. Players have to guess opponents' hands from their actions—tricky for computers. Poker has become a new benchmark for AI research. Solving poker could lead to many breakthroughs, from cyber security to driverless cars.

    Scientists believe it is only a matter of time before AI once again vanquishes humans, hence our human-machine match comes up in a game of Texas Hold's Em Limit Poker. The AI was developed by Johannes Heinrich, researcher studying machine learning at UCL. It combines two techniques: neural(神经的) networks and reinforcement learning(强化学习).

    Neural networks, to some degree, copy the structure of human brains: their processors are highly interconnected and work at the same time to solve problems. They are good at spotting patterns in huge amounts of data. Reinforcement learning is when a machine, given a task, carries it out, learning from mistakes it makes. In this case, it means playing poker against itself billions of times to get better.

    Mr Heinrich told Sky News: “Today we are presenting a new procedure that has learned in a different way, more similar to how humans learn. In particular, it is able to learn abstract patterns, represented by its neural network, which allow it to deal with new and unseen situations.”

    After two hours of quite defensive play, from the computer at least, we called it a draw.

With fuel costs rising and airlines finding more fees to impose （强加，征税）on travelers every day, airfare isn't getting any cheaper. Since you can't drive to all your dream destinations, flying is the only way to go sometimes and, undeniably, the fastest. Luckily, there are plenty of ways to find the most affordable fares and also avoid paying as many extra charges as possible when you plan ahead.

    Get the best fare. Airlines put out their fare sales on Tuesday morning, making this day the best day to book a flight for less.

Fly during the least popular times. Tuesday, Wednesday and Saturday are the slowest days to fly, which means cheaper deals than the rest of the week. You can also find reduced rates on early morning flights, since many people don't like to get up before the sun to get to the airport. Earlier boarding times can also considerably cut down your chances of getting bumped on an overbooked flight or delayed because of other delayed flights or mechanical issues.

    Choose your seat later. Some airlines charge you to pick your seat when you book online, adding even more to the bottom line of your ticket cost. If you show up early on your travel day, you can still get suitable seats. Some of the best seats get held back until flight day, unless others are willing to pay extra for them ahead of time, so you still have the chance at one of those.

Fly on holidays. You already know that summer is the most expensive time to fly, and even though most other times are more affordable, the days surrounding holidays can be crazy. Save big if you're willing to travel on major holidays, such as Thanksgiving and Christmas.

Don't wait until the last-minute to book. Many travelers don't know that there's a sweet spot for booking and getting the best price on your tickets. Book too early or too late and you could end up paying more than you need to. The best time to book is between three months and six weeks from when you want to travel.

    In recent decades, social isolation has been recognized as a major risk to our health and long life. It's twice as bad for you as being overweight and nearly as bad as smoking. The rising number of people who say they are affected, across a wide range of ages, is shocking. In reality, you can suffer the ill effects of loneliness even if you are not socially isolated.

Comedian Robin Williams made a striking observation in 2014: "I used to think the worst thing in life was to end up all alone. It's not. The worst thing in life is to end up with people who make you feel all alone." Tracking large groups over time indicates that perceived（感知的）social isolation carries its own risk for morbidity（发病率）and mortality.

    The perception of isolation—from others of being in the social aspect-is not only a cause of unhappiness, it also signals danger. Fish have evolved to swim to the middle of their group when predators（捕食者）approach, mice housed in social isolation show sleep disruptions and reduced slow-wave sleep and prairie voles（田鼠）isolated from their partners then placed in an open field explore their surroundings less and concentrate on avoiding predators.

    These behaviours reflect an increased emphasis on self-preservation in the social aspect. For instance, fish on the edge of a school are more likely to be attacked by predators because they are easier to isolate and prey upon. Such observations reflect a more general principle that perceived social isolation in social animals activates neural（神经系统的）, neuroendocrine（神经内分泌的）and behavioural responses that promote short-term self-preservation. However, these responses bring a cost for long-term health and well-being.

    The range of harmful neural and behavioural effects of perceived isolation documented in adults include increased anxiety, hostility and social withdrawal; fragmented sleep and daytime tiredness; increased vascular resistance and changed gene expression and immunity; decreased impulse control; increased negativity and depressive symptoms; and increased age-related cognitive decline.

    Sadly, to date, attempts to reduce loneliness have met with limited success. A series of randomized controlled trials showed that they had only a small effect. Among the four types of interventions（介入）examined, talking therapy that focused on inappropriate thought processes had the largest impact. Social skills training, social support and increased opportunities for social contact were much less effective.

You might think people all over the United States have Wi-Fi—wireless Internet service—and mobile phones. But there is no such service in Green Bank, West Virginia, a tiny town four hours from the U.S. capital, Washington D.C. Fewer than 150 people live in Green Bank, which has two churches, an elementary school and a public library. It is also home to the largest radio telescope in the world.

    There is a ban on Wi-Fi in Green Bank, along with anything else that can create electromagnetic(电磁的)waves. Officials say the waves could disturb the signals the telescope receives.

For many Americans, a visit to Green Bank is a little like returning to the 1950s. To get there, you must read road signs—because there is no GPS service in the town. People can connect with the Internet through telephones, but wireless service is not allowed.

    The observatory(天文台)is one of the largest employers in the area. The federal National Science Foundation(NSF) spends about ＄8.2 million a year to operate the observatory, telescope and educational center.

    Jonah Bauserman is a technician. If he supposes there is signal that is not allowed in the zone, he drives to the house where the signal is coming from and checks it. But once a week, when the device is cleaned, some banned devices are allowed near it.

    People in the town respect the work of the scientists. And they say they are happy to live without Wi-Fi and mobile phones. “You know, instead of sitting here on our phones and other devices we're out fishing and hunting and going to each other's houses.” Everyone knows each other and communication is almost always face-to-face.

    Dutch officials toasted on Tuesday the opening of what is being called the world's first 3D-printed concrete bridge, which is meant to be used by cyclists. There was applause as officials wearing hard hats and workmen's jackets rode over the bridge on their bikes at the opening ceremony in the southeastern town of Gemert.

    “The bridge is not very big, but it was rolled out by a printer which makes it unique,” Theo Salet, from the Eindhoven University of Technology, told Dutch broadcaster NOS. Work on printing the bridge, which has some 800 layers, took about three months after starting in June and it is made of pre-stressed concrete, according to the university. “One of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mould (泥浆) is filled,” it said on its website, adding “a printer deposits the concrete only where it is needed.”

    The eight-metre (26-foot) bridge crosses a water-filled channel to connect two roads, and it was tested for safety to bear loads of up to two metric tons in cooperation with the BAM Infra Construction company. Although designed for bikes, it could take up to 40 trucks, the designers said “We are looking to the future,” said the head of BAM, Marinus Schimmel. “3D printing meant fewer rare resources were needed and there was significantly less waste,” he added.

    The Netherlands is among countries, with the United States and China, taking a lead in the cutting-edge technology of 3D printing, using computers and robotics to construct objects and structures from scratch without using much traditional manpower. Last year a Dutch architect unveiled (提示) a unique 3D printer with which he hopes to construct an “endless loop” building. And a Dutch start-up called MX3D has begun printing a stainless-steel bridge, of which a third is already completed. The aim is to finish printing by March and lay the bridge over an Amsterdam canal in the future.

The hens look up at me from their nesting boxes. They seem slightly annoyed but unsurprised. A child runs up, pushes one of the chickens aside, and snatches two eggs. Around me, a half-dozen more children and adults collect eggs while a half-dozen others hand-feed dried mealworms to birds flocking around our ankles. I reach for an egg from an empty nest. There is something perfect about the way it fits warmly in the palm of my hand before I transfer it into a pretty wire basket provided to me by my hosts. 

The egg harvest is a brief, carefully designed agritourism experience offering an experience of the labor rather than just having a bite of food. Snatching a few eggs and uprooting a few vegetables on the farm tour donˈt constitute a full dayˈs work, but it is also a useful reminder that food doesnˈt just magically appear on restaurant plates and grocery store shelves. Of course, visitors can take those eggs home or bring them to the on-farm restaurant, Clay, where a chef will use them to prepare breakfast. 

A few centuries of industrialization, urbanization, and globalization have collected people into cities, but the attraction of the countryside has always remained. In the new urban-centered world, enterprising farmers have found plenty of opportunities to sell their rural lifestyle along with their crops. Italy promoted the modern model for combining agriculture and tourism in the wake of World War Ⅱ, when the national government encouraged rural populations to continue producing food rather than move to urban areas in search of more profitable jobs. 

Agritourism acts as an umbrella term for a wide variety of activities that take place on farms, including farmstays, where guests sleep on-site. For varying investments of time, energy, and money, anyone can engage in our farming system, giving consumers a peek behind the farm-to-table world.