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A new study of older adults finds excessive daytime napping (小睡) may signal an increasing risk of Alzheimer's disease. Investigators from Brigham and Women's Hospital report a relationship between daytime napping and cognitive (认知的) aging: excessive daytime napping predicts an increased future risk of Alzheimer's, and a diagnosis of Alzheimer's speeds up the increase in daytime napping during aging.

"Daytime sleep behaviors of older adults are often ignored, and a consensus (共识) for daytime napping in clinical practice and health care is still lacking," said Peng Li of the Medical Biodynamics Program in Brigham's Division of Sleep and Circadian Disorders. "Our team calls for a closer attention to 24-hour sleep patterns — not only nighttime sleep but also daytime sleep — for tracking the health of older adults."

Researchers at the Brigham recognized that all previous studies on Alzheimer's disease assessed napping within a participant only once, most of which were subjective and questionnaire-based. In the new study, more than 1000 individuals, with an average age of 81, were provided Actical, a watch-like device, to wear on their wrist for up to 14 days. After napping episodes were identified, the nap duration and frequency were calculated.

The results suggest that excessive daytime napping may signal an increasing risk of Alzheimer's, and that faster yearly increase in daytime napping may be a sign of worsening or unflavored clinical progression of the disease.

Researchers acknowledge that although the method of the new study has been widely used in sleep field studies, they recognize that polysomnography (多导睡眠记录仪) is the gold standard for sleep scoring. Moreover, the participants studied were older, and therefore, the findings may not be easily translated to younger people. In addition, future studies should test whether a direct intervention in daytime napping can lower the risk of Alzheimer's or cognitive decline.

"We hope to draw more attention to daytime sleep patterns and the importance of patients noting if their sleep schedule changes over time," said co-senior author Kun Hu of the Medical Biodynamics Program. "Sleep changes are critical in shaping the internal changes in the brain."

The world's biggest electric vehicle — a 45-ton mining dump truck named the eDumper — may have to give up its throne. A newcomer powered with both electricity and a reserve of hydrogen fuel, is going to steal that title as the largest electric mining truck.

London-based Anglo American is developing the beast of a machine — it weighs 290 tons — as part of its sustainable mining vision. The conceptual work is done, but UK-based Williams Advanced Engineering will bring the truck to life. The idea is to replace the vehicle's diesel engine (柴油机) with a high-power modular lithium-ion battery (锂电池). "We are delighted to be involved in this innovative and exciting project which shows the potential of battery technology that can adapt to increased demands, from automotive and motorsport to ‘heavy duty' industrial applications," Craig Wilson, managing director of Williams Advanced Engineering, said.

While the eDumper — a mining truck used to move stones from the sides of mountains in Switzerland — relies entirely on pure electricity and pure physics for power, the Anglo American truck will use both a lithium-ion battery and hydrogen fuel cell (电池) module. Altogether, the new truck will have over 1,000 Kilowatt hours of energy storage.

Hydrogen fuel is a clear fuel that produces only water as a by-product when consumed in a fuel cell. It's typically produced from natural gas, nuclear power, or renewable wind and solar power. Adding hydrogen fuel cells to the vehicle's battery will allow the truck to run for longer periods of time without recharging.

There's also a third type of power that comes into play with the Anglo American truck: kinetic (动力的) energy created through the process of regenerative braking (再生制动系统). When an electric vehicle — be it the Anglo American truck, or the eDumper — rolls down a hill, that movement creates electrical energy for the battery as you brake. The electric motors power the car through the battery's stored energy, but can also become mini generators that return some energy back to the battery.

After Anglo American finishes test trials with the truck, the firm will conduct studies to understand how the truck's power units can be used to provide energy storage in other applications.

Bookstores, like wines, have different notes, different flavors, each one distinct. There are the musty (有霉味的), odd ones with random piles and dusty rows, usually with both used and new books. There are small independent stores charming and cozy. Then there's the big-box with long, straight rows, bright and dustless, usually featuring a cafe and a kids section you can get lost in.

My adoration for bookstores is, without a doubt, partly nostalgic (怀旧的). I came of age in the late 1990s, when Amazon was mostly known as a river in South America, phones were not smart____and bookstores were dotted around cities.

When my husband and I were dating, our go-to date was to get coffee and walk around bookstores together. It was the best. We'd move slowly, wandering through the religion section, the memoirs, fiction, poetry, history. I'd pick up a title I'd heard about and sit in the aisle reading a chapter. I'd find one I'd never heard of and scan the back cover. We'd sip our coffee and read each other interesting paragraphs from books we found.

I fell for bookstores and for my husband at the same time. So when stores began closing down all over America, we were both sorrowful. What were we supposed to do with a night out now?

In a recent very informal and unscientific poll (调查) of my friends, I found that many of us love and miss physical bookstores. Friends described the feeling of discovery and exploration, the calming serenity (宁静) of being surrounded by words and ideas. My wise friend Greg said, "Bookstores are like the best parties: You may discover a new friend or join an unexpected conversation with a simple turn of your head."

I dream of an America with streets full of independent bookstores whose inventories (库存清单) contradict one another. But right now I'm in favor of any brick-and-mortar (实体的) book store, really. Any place that reminds us that the material world is beautiful and worth spending time in. Any place where we can learn how to exist together in communities full of words and ideas. Any place where we may discover something unpredictable and new. And if there's coffee nearby, even better.

Space Center Houston offers a variety of age-appropriate and inspiring camp experiences with safety top of mind. In the wake of COVID-19, we aim to continue inspiring all generations through the wonders of space exploration while maintaining the highest level of safety for all. Our Explorer Camps introduce children ages 4-11 to science, technology, engineering and math through engaging and hands-on learning activities. Discover and explore our Explorer Camps for ages 6-7 and below.

JOURNEY TO MARS

June 14-18, July 12-16, Aug. 9-13    $289.95       5-DAY EXPLORER CAMP

While demonstrating best safety practices, campers are involved in activities that arouse their interest in science along with their sense of adventure. These young engineers learn the basic of rocketry, discover coding and explore hands-on science activities.

ENGINEERING BASICS

June 7-11, July 5-9    $289.95       5-DAY EXPLORER CAMP

Campers discover what it takes to solve problems related to space exploration in Engineering Basics. Taking LEGO bricks "out of the box" and to new and exciting places, this camp gets your little builders using LEGO bricks like never before. These engineers-in-training will participate in problem-solving activities, building simple machines, art projects, and robotics.

JOURNEY TO SPACE

June 28-July 2, July 26-30    $289.95        5-DAY EXPLORER CAMP

How do astronauts work in space? Why is Venus so hot? Will people ever go to Mars? How do robots work? What do engineers do? All these questions are answered as campers explore space through art, science, robotics and engineering activities. This camp leaves all inquiring minds inspired to continue their journey.

EXPLORATION AND DISCOVERY

June 1-5    $229.95       5-DAY EXPLORER CAMP

Campers discover what it takes to send people, supplies and spacecraft beyond Earth's atmosphere. During this five-day adventure, former astronauts will deliver speeches on how they live and work in the space station.

注意： 1.词数100词左右；2.开头和结尾已给出，不计入总词数。

"Choose your friends wisely" may not only be good parental advice but also a way to do better in college, a research study finds. Researchers prove that students who befriend studious peers spend more hours studying themselves and post higher grades during their freshman year.

It's important to clarify that having smart friends isn't as important as having studious friends in this study. The researchers didn't find that friends' grades mattered. What influenced a student's college grades were his or her friends' high school study habits. To be sure, students with higher grades tend to have better study habits.

They also found that, for every additional 10 hours a week that a student's friends had spent studying in high school, on average, the student's own study time in college would likely increase by almost 25 minutes a day, and the student's own GPA (Grade Point Average) would likely rise by almost a tenth of a point during freshman year. Almost identical results are among freshman roommates randomly assigned by the college, which confirms that peers are actually influencing study habits and echoing the friendship analysis. The researchers controlled for gender, race and prior academic achievement and found that the positive influence of studious peers was similar for both high achieving and low achieving students.

The difference between a B and B+ average is 

0.3 points, so studious friends are only nudging grades up a bit. That means peers are just one of many factors influencing how well students do in college. So should we encourage parents to pick their kids, friends in college? "This is one outcome-GPA．There are other things in life, said Mehta who admits to selecting studious friends when he was in college.

A study revealed that, in most occasions, the outcome on a given task can be improved when two people have helped each other instead of working on their own. As early as 1624 John Donne has already popularized the phrase "No man is an island". And this is especially true, be it in the workplace, in doing scientific research, or working in events. One of the benefits of cooperation is that people can pool together their skills and wisdom towards a common aim. Because of this, they have a higher chance of being more successful.

Teamwork promotes diversity. The very nature of teamwork requires a group of people from various backgrounds to come together and share their thinking.  This level of diversity generates cultural understanding, increased communication through collective knowledge of approaches and a larger resource of opinions.

 Working within a team helps us to create an environment which inspires collective knowledge, resources and skills. Consequently, this allows us to pick some ideas and to reflect on our own way of thinking. Teamwork also encourages self-improvement because it helps us to expand our horizons and make better use of our own intrinsic capabilities. And since self-improvement helps us in seeking better ways to perform our role within a team, it improves both the efficiency and productivity of the team as a whole.

Completion of task becomes easy. Each member has unique skills to help with the project. For example, you may ask one person to do research, another to take charge of social media marketing, and another to look after delivery. Teamwork can get the most of each person's strengths.

 For instance, tackling about climate change by researchers who come from different disciplines (学科) could potentially lead to ground-breaking researches. In the traditional research world, one researcher pursued a theme over several decades. However, academia is fostering a fresh research culture, whereby academic works advance through the creation of interdisciplinary research.

A．Teamwork encourages healthy competition.

B．It promotes peer learning and self-improvement.

C．So a task can be assigned based on a person's skills and expertise.

D．There are many benefits we can gain out of teamwork and cooperation.

E．The seeds of creativity and innovation spring from the exchange of ideas.

F．As a result, different opinions and problem-solving methods can be formed.

G．Cooperation has several benefits including shared risk, resources and knowledge.

After years of observing human nature, I have decided that two qualities make the difference between men of great achievement and men of average performance curiosity and discontent. I have never known an outstanding man who lacked either. And I have never known an average man who had both. The two belong together. 

Together, these deep human urges（驱策力）count for much more than ambition. Galileo was not merely ambitious when he dropped objects of varying weights from the Leaning Tower at Pisa and timed their fall to the ground. Like Galileo, all the great names in history were curious and asked in discontent, "Why? Why? Why?"

Fortunately, curiosity and discontent don't have to be learned. We are born with them and need only recapture them. 

"The great man," said Mencius（孟子）, "is he who does not lose his child's heart." Yet most of us do lose it. We stop asking questions. We stop challenging custom. We just follow the crowd. And the crowd desires restful average. It encourages us to occupy our own little corner, to avoid foolish leaps into the dark, to be satisfied.

Most of us meet new people, and new ideas, with hesitation. But once having met and liked them, we think how terrible it would have been, had we missed the chance. We will probably have to force ourselves to waken our curiosity and discontent and keep them awake. 

How should you start? Modestly, so as not to become discouraged. I think of one friend who couldn't arrange flowers to satisfy herself. She was curious about how the experts did it. Now she is one of the experts, writing books on flower arrangement.

One way to begin is to answer your own excuses. You haven't any special ability? Most people don't; there are only a few geniuses. You haven't any time? That's good, because it's always the people with no time who get things done. Harriet Stowe, mother of six, wrote parts of Uncle Tom's Cabin while cooking. You're too old? Remember that Thomas Costain was 57 when he published his first novel, and that Grandma Moses showed her first pictures when she was 78.

However you start, remember there is no better time to start than right now, for you'll never be more alive than you are at this moment.

Infectious diseases and associated deaths have reduced, but they remain a significant threat throughout the world. Infectious diseases outbreaks and the fear and panic that accompany them present various economic risks. 

First, there are costs to the health system, both public and private, of medical treatment of the infected and of outbreak control. Concern over the spread of a relatively contained outbreak can lead to decreased trade. Travel and tourism to regions affected by outbreaks are also likely to decline. Some long-running outbreaks, such as HIV, prevent foreign direct investment. 

The economic risks are large. It is estimated that the expected yearly cost of infectious diseases is at roughly $500 billion. Even when the health impact of an outbreak is relatively limited, its economic consequences can quickly become expanded. Liberia, for example, saw GDP growth decline 8 percentages from 2013 to 2014 during the Ebola outbreak in Africa.

The risk is complex, but policymakers have tools in response.

Investing in improved health care, supply of clean water, and better health systems can reduce the frequency of human contact with viruses. Investment in reliable disease monitoring in both human and animal populations is also critical. Within formal global watch systems, instead of discouraging reporting possible outbreaks, it may be beneficial to develop incentives for reporting suspected cases, as countries may reasonably fear the effects of such reporting on trade, tourism, and other economic outcomes. Informal monitoring systems, social media for example, which collect information from official reports, media reports, online discussions, and eyewitness observations, can also help national health systems and international responders get ahead of the outbreak news during the early stages. Cooperations for monitoring infectious diseases readiness at the national level provide information national governments can use to react timely to their outbreaks.

There is a significant market failure when it comes to vaccines (疫苗) against individual low-probability viruses that collectively are likely to cause panic. Given the low probability that any single vaccine of this type will be needed, high Research and Development (R&D) costs, and delayed returns, medical companies hesitate to invest in their development. However, responsible international corporations such as CFPI can overcome this market failure. Its goals include advancing candidate vaccines against specific low-probability, high-severity viruses through proof of concept to enable rapid clinical testing in the event of outbreaks. It also aims to fund development of institutional and technical platforms to speed R&D in response to outbreaks for which there are no vaccines.

Undoubtedly, humans and infectious viruses will coexist. However, we can take effective measures to manage the risk of the diseases. Joint action now at the local, national, and multinational levels can go a long way toward protecting our collective well-being in the future.

Recycling Electronic Waste

When Alex Lin was 11 years old, he read an alarming article in the newspaper which said that people were burying old computers in backyards, throwing TVs into streams, and dumping (丢弃) cell phones in the garbage. This was dangerous because e-waste contains harmful chemicals that can leak into the environment, getting into crops, animals, water supplies — and people.

Alex was really worried and decided to make it next project for WIN—the Westerly Innovations Network. Alex and six of his friends had formed this organization to help solve community problems two years before.

But what could they do about this project with e-waste? The team spent several weeks gathering information about the harmful chemicals in e-waste and their effects on humans. They learned how to dispose (处置) of e-waste properly and how it could be recycled. Then, they sent out a survey and found only one in eight knew what e-waste was, let alone how to properly dispose of it.

Alex and his friends went into action. They advertised in the local newspaper and distributed notices to students, asking residents to bring their unwanted electronics to the school parking lot. The drive lasted two days, and they collected over 9, 500 kilograms of e-waste.

The next step was to set up a long-term e-waste drop-off center for the town. After some research, they'd learned that reusing is the best way to deal with electronic devices and it is seven times more efficient than recycling. So, they began learning to refurbish (翻新) computers themselves and distributed them to students who didn't have their own. In this way, they could help students in the area and protect the environment at the same time.

For a lasting solution to e-waste, the drop-off center wasn't enough. Laws would have to be passed. In 2016, WIN helped push for an e-waste bill in their town, which required companies that manufactured or sold electronics to take back e-waste. The bill clearly forbids the dumping of e-waste.

Because of the work of WIN, more and more people, like Alex and his team, are getting the message about safe disposal of e-waste. As Alex says, "Today's technology should not become tomorrow's harmful garbage."