【推荐1】What’s really green?

Most of us are aware that we must protect the environment. But recently, some “green truths” have turned out only half true, or even completely false. Here are some common ones.

Paper shopping bags are better than plastic ones.

Plastic bags cause litter, bring dangers to wild animals and take long to break down. So people think paper bags are better. However, making a paper bag uses four times as much energy as making a plastic bag and three times the amount of water, besides producing more greenhouse gases.

Actually, neither are environment-friendly. So, take a reusable bag with you when shopping.

Running your car air conditioning burns more gas.

Running your car air conditioning (A/C) will affect your gas mileage, costing you more money and producing more pollution. However, if you want to save gas by turning off the A/C and rolling down your windows, you have to drive at low speed. At high speed, the aerodynamic drag (空气阻力) caused by open windows will actually cost you more gas. It does help save some gas if you turn off your A/C a few minutes before arriving at your destination.

It’s better to take a shower than a bath.

It depends on your shower time and size of your bath. If you spend over eight minutes in a shower, you’ll use as much water as in a bath. Therefore, the key is to keep your shower time as short as possible.

When you turn off a device, it stops using power.

When we turn off a device like television, it goes into stand-by mode. However, devices in this mode still use power. To ensure your device is truly off, just remove the plug (插头).

【推荐2】In today’s world, sleep experts say that for a better night’s rest, Americans should turn off their smartphones or iPad before sleeping. Such electronic products make the brain more active, and then influence their sleep. But according to a latest survey, more than 90% of Americans regularly use a computer or some other kinds of electronic products in the hour before bed.

Researchers are finding that man-made light from some electronic products at night may reduce the brain chemicals(化学物质) that help sleep. The researchers showed that sitting in the light from computer tablets clearly lowered levels of the chemical which manages our body clocks and plays a role in the sleep cycle.

In the study, the researchers let volunteers read, play games and watch movies on a tablet for different time while measuring(测量) how much light their eyes received. They found that two hours of sitting before a bright tablet screen at night reduced the sleep chemical levels by about 22%.

Studies of students using computers at night have got the similar results. And researchers say that may not only cause sleeplessness, but also raise the risk of obesity(肥胖症), diabetes(糖尿病) and other diseases.

To be on the safe side, the researchers advise us to use computers less before bed, or at the very least turning down your screen as much as possible.

【推荐3】Many of us have experienced the following: the day before an exam, we try to squeeze a huge amount of information into our brain. But just as quickly as we acquire it, the knowledge we have gained is gone again. The good news is that we can solve this problem. With expanded time intervals between a person’s learning events, we keep the knowledge for a longer time.

But what happens in the brain during the spacing effect? It is generally thought that during learning, neurons (神经元) are activated and form new connections. In this way, the learned knowledge is stored and can be regained by reactivating the same set of neurons. However, we still know very little about how pauses positively influence this process.

Neurobiologists Annet and Pieter did an experiment, during which mice had to remember the position of a hidden chocolate piece in a maze (迷宫). On three continuous chances, they were allowed to explore the maze and find their reward—including pauses of different lengths. “Mice trained with the longer intervals between learning phases (阶段) were unable to remember the position of the chocolate as quickly,” explains Annet. “But the next day, the longer the pauses, the better was the mice’s memory.”

“If three learning phases follow each other very quickly, we naturally expect the same neurons to be activated,” Pieter says. “After all, it is the same experiment with the same information. But after a long break, we imagine the brain interprets the following learning phase as a new event and processes it with different neurons.”

However, the researchers found the opposite. In fast continuous learning phases, the mice activated mostly different neurons. When taking longer breaks, the same neurons active earlier were used again later. Reactivating the same neurons could allow the brain to strengthen the connections between these cells. With spaced learning, we may reach our goal more slowly, but we benefit from our knowledge for much longer.

【推荐2】If you’ve experienced the care of a kind hardworking doctor, one way to thank your doctor is writing a thoughtful thank-you note. Finding the right words isn’t always easy. To help you create a meaningful message for the doctor, you can learn from the thank-you notes below.

The first example: Post-surgery (术后) thank-you note

Thank you so much for your excellent work during my foot surgery. I experienced the least pain during the recovery. I feel much better now, and I am confident that I’ll be returning to my favorite sport soon. Your kindness and devotion to patients really shine bright in everything you do. Thank you again.

The second example: Post-delivery (产后) thank-you note

Dear Pam Smith, thank you for delivering my baby. All of your care and concern leading up to the delivery made me feel confident in going into the delivery room. The baby class you recommended was a lifesaver, and I can’t thank you more for your help through this entire process.

The third example: Say thanks for taking care of your loved one

Thank you for your kindness with my mother, Susan Meyer. The entire family was concerned when she fell sick last month, and you really helped us a lot. If it weren’t for you, I don’t know how I would have handled everything as an office lady. My mother is better now. We all send our love and thanks!

The fourth example: Say thanks to your family doctor

I appreciate your reliable care year after year. Your guidance during my annual physical keeps me in my best shape, and I owe much of my success to you. Best wishes from a dedicated patient.