How do you get a good night's sleep?

    You may put your pillow (枕头) at the proper height, drink a glass of hot milk or maybe listen to some light music before bedtime. {#blank#}1{#/blank#}When World Sleeping Day falls on March 21, it will be a good time to explore a long-ignored fact that may make you feel tired after you wake up. Scientists have discovered that the position of your spine (脊椎) is very important when you sleep.

    {#blank#}2{#/blank#}Let's have a look at the advantages and disadvantages of each position.

On your back

    Sleeping on your back is the ideal (理想的) position to be in. First of all, your spine is in the best position.{#blank#}3{#/blank#}The downside is the greater likelihood of snoring (打鼾) and sleep apnea (窒息).

Lying on belly

    {#blank#}4{#/blank#}Dr Vaclav Vojta, a US child development specialist, said this is bad for your back because it takes away the natural curve (曲线) of your lumbar (腰部的) spine. But he also noted that this helps to prevent some snoring and sleep apnea.

On your side

    Sleeping on our sides happened naturally while we were in the womb (子宫).{#blank#}5{#/blank#}Plus, sleeping on your side (the left side in particular) has been reported to reduce troublesome digestive problems like heartburn. The downside is the “dead arm” and finger numbness (麻木) from this position.

A. Lying face down with your legs straight and your arms right by your sides is a bad idea.

B. Sleeping on your side can be a quick fix for snoring and can help to improve breathing.

C. Do you and your friends ever talk about your sleeping position with each other?

D. And a new study suggests that the sleeping position has something to do with it.

E. Of the three sleeping positions, which one do you usually go for?

F. You are also less likely to have digestive (消化的) problems.

G. But one thing you may tend to ignore is sleeping positions.

Like many Czechs (捷克人), Lukáš Berný, 38, enjoys going out to the pub with his friends for conversation and a few beers. "I don't drink every day," he says. "I think about three times a week. When I go out, I usually have five to six beers at a time, about the same as my friends." The beers are half-liters, or 500ml each.

    If a half-liter of four-percent beer contains 16g of pure alcohol（酒精）, Berný and his friends are drinking 80 to 96 grams of pure alcohol on each outing. The Czech Republic's National Institute of Public Health, however, suggests that men take in fewer than 24g of pure alcohol per day; women, fewer than 16g.

Medical experts in over 40 countries around the world have agreed that drinking "too much" can cause harm. What they can't seem to agree upon is just how much is "too much." National safety levels are quite different, from a limit of 10g a day in the Netherlands to Denmark's 60g.

There are a number of reasons for this. Dr. Larry Altshuler, a medicine expert for the Cancer Treatment Centers in Tulsa, explains that while everything is based on research, "Every group, race, and gender responds to alcohol differently."

Also, researchers aren't using the same models or methods. He adds, "It can be like apples and oranges. How do you measure alcohol? Units, drinks, bottles or cans? What's the alcohol content（含量）? Is it light or heavy?" While a half-liter of four percent beer contains 16g of pure alcohol, a half-liter of five percent lager contains 20g.

Constance Scharff, a director of Addiction Research at Cliffside Malibu Treatment Center in California, says she believes the reason "is largely cultural." "But the evidence is clear that the more you drink, the more likely you are to develop alcohol-related health problems."

    In February, 2015, a South Korean woman was sleeping on the floor when her robot vacuum ate her hair, forcing her to call for emergency help. It surely isn't what Stephen Hawking warned us that intelligent devices “mean the end of the human race”. But it does highlight one of the unexpected dangers of inviting robots into our home.

    There are many examples of intelligent technology going bad, but more often than not, they involve cheating rather than physical danger. Meanwhile, increasing evidence suggests that we, especially children, tend to tell our deepest, darkest secrets to human robots. So how do we protect ourselves from giving-away code?

    Once you've invited a robot into your home, you need to manage your expectations. Movies and marketing may have told us to expect deep interaction with robots friends but we've still got a long way to go before they are as socially aware as described. Given the gulf between expectation and reality, it's important to avoid being tricked.

    The message is clear: as robots became increasingly connected to the internet, and able to respond to natural language, you need to especially cautious about figuring out who or what you are talking about.

    We also need to think about how information is being stored and shared when it comes to robots that can record our every move. Some recording devices may have been designed for entertainment but can easily be adapted for more dangerous purposes. Take Nixie, the wearable camera that can fly off your wrist at a moment's notice and take shots around you in the air. It doesn't take much imagination to see how such technology could be taken advantage of.

    If the technology around us is able to record and process speech, images and movement, or listen secretly to us, what will happen to that information? Where will it be stored? Who will have access?

    So, what is the safest way to welcome robots into our homes, public spaces, and social lives? We should be cautiously optimistic that intelligent machines could become enriching companions, while acknowledging that we need to determine strict boundaries for robots. There should be someone to turn to should your robot commit a crime, steal your card... or try to eat your hair.

    A study found wireless signals are able to pass through bags and suitcases to judge the sizes of dangerous metal objects and identify them." These items could include weapons, chemicals, laptops and batteries for bombs, "the research team said on Tuesday.

    Research suggested that Wi-Fi can now be used to estimate the volume of liquids such as water, acid, alcohol and other chemicals for explosive material. The study led by researchers at the Wireless Information Network Laboratory (WINLAB) in the School. of Engineering showed a wireless device with two to three antennas(天线)that could be fitted in existing Wi-Fi networks.

    The detection system analyzes what happens when wireless signals go through and bounce off objects or materials. The approach, which the paper states, works by separating the wireless interference(干扰)caused by two factors of objects-the material and shape." Most dangerous objects such as weapons are usually metal or liquid, which have significant interference," researchers said.

    When it was tested on a backpack, the accuracy rate topped 95 percent. "But the accuracy dropped to about 90 percent when objects inside bags are wrapped. And the tech could save lives if used in museums, stadiums, theme parks or schools," the team said, noting its design can inspect bags or luggage without being an exposure to privacy.

    It uses channel state information (CSI) that is readily available in low-cost Wi-Fi devices." This could have a great impact on protecting the public from dangerous objects," said Yingying Chen, a co-author of the study," There's a growing need for that now. In large public areas, it's hard to set up expensive screening equipment like what's in airports. Manpower is always needed to check bags and we want to develop a method to try to reduce manpower.”

    The peer-reviewed study, which recently won a best paper award at the 2018 IEEE Conference on Communications and Network Security, is now published online." Future work will continue to focus on ameliorating the accuracy of identifying objects and imaging shapes and volumes," researchers said.

Planning Your Family Trip

    Plan ahead to make your family trip run smoothly. Family vacations are cherished memories. Keeping children entertained on the road or during a flight, however, can be challenging. The best way to cut down on anxiety? Plan ahead.

    Avoid giving children snacks that contain sugar and caffeine. Sweet treats keep them happy and quiet for five minutes, as it fills them with unusable energy that will turn into crankiness (偏执) when the sugar wears off. Bring fun, small snacks like flavored baked chips, apple sauce, raisins, and granola bars—and top it off with a little protein like cheese sticks to keep the blood sugar levels nice and steady.

    Bring plenty of plastic or paper bags. This is the perfect time to put those spare bags around the house to use. Store them in your purse or pocket, as well as in the car. This is a quick solution for garbage, diaper wrapping or motion sickness.

    Avoid extra costs on bulk items you will need during the trip. When flying, purchase bulk items like diapers, formula, and wipes at your destination. In the past, it was convenient and free to check these items. Now, each checked luggage item costs $25 or more on average. When driving, do the opposite; take your bulk items to avoid extra trips to the store when you arrive, which can help you avoid impulse travel purchases.

    Bring a full change of clothing for each child. Keep these items within fairly easy reach. When a spill or mess happens, this will help parents avoid unexpected (and unbudgeted) clothing purchases.

    Travel planning can help make family vacations what they are supposed to be: Fun! What are some of your favorite strategies for saving time and stress while traveling with children?

Steager is an engineer at the University of Pennsylvania. His colleague Hyun Koo is an inventor and dental researcher there. Together, they found a way to form the nanoparticles（纳米颗粒）into long, skinny bristles（鬃毛）, a lot like the ones on a toothbrush. But these bristles shape-shift to fit whatever surface they encounter. They can even squeeze between teeth.

"A new way to clean teeth could help out anyone who finds this chore boring," says Koo. But it would be especially life-changing for people with disabilities or illnesses that make it difficult or impossible to hold and move a toothbrush.

The tooth-cleaning robot works thanks to two magnets（磁铁）. One goes on each side of the teeth. The nanoparticles sit in a water-based solution between the magnets. When the magnets are turned off, the nanoparticles float randomly in the solution. As soon as one magnet gets turned on, the nanoparticles clump together near its center. When you turn on the other magnet and turn off the first one, the nanoparticles extend outward in long, skinny bristles.

When there's a tooth in the way, these bristles can't stretch out as far as they want. So they push against the tooth's surface. If there's a gap between teeth, they push into the gap. Moving the magnets makes the bristles move against and between teeth.

Besides, as a bonus, the nanoparticles can kill what harms the teeth and keep them health y because it contains something commonly added to toothpaste and mouthwash.

The new invention is just a proof of concept. The researchers still need to turn it into a product that people will want to use. It must fit comfortably and safely in people's mouths. It can't draw too much power or cost too much. "There's a lot of engineering to get from here to there," says Steager. But he adds, "every good idea needs to have a start."