Early birds-people who feel most energetic in the morning-tend to make healthier food choices throughout the day than night owls(夜猫子) , according to a new study.

    "Evening types had more irregular meal times," notes study author Mirkka Maukonen, studying human nutrition and obesity(肥胖) in Finland.

    Her study focused on people's risk of heart disease and their eating habits. Participants described when and what they had eaten during the past two days.

Maukonen's team then looked at l,854 people's lifestyle. After analyzing the data, the researchers found that both morning and evening people consumed approximately the same number of calories over a whole day.  However, night owls tended to eat their meals later than early birds. Before 10:00 am, night owls consumed less food than early birds. More of their calories came from sugar. After 8:00 pm, the night owls ate more sugar and fat. Meanwhile ,early birds ate more protein during both the morning and the evening hours.

    "Night owls tend to be less healthy than early risers," notes Courtney Peterson who studies diet and meal timing. "They are more likely to get heart disease or cancer. The fact that night owls tend to eat more junk food probably plays a role," Peterson says. "Other factors(因素) also can ruin a night owl's health. Night owls generally sleep worse," says Peterson. "Poor sleep has been linked to unhealthy food choices. "

    Peterson and Maukonen say night owls tend to have poor eating habits. But that doesn't necessarily mean that being a night owl makes a person a poor eater. It could be the reverse- eating poorly could affect people's sleep habits.

"The new findings should serve as a wake-up call to night owls. For them, the new results should encourage paying attention to healthier lifestyle choices," says Maukonen. 28. How did Maukonen do research about people's risk of heart disease?

    If you want to fully enjoy your vacation, you'd better check the Durban City Tours! This is actually one of the best choices in South Africa today.

    There is nothing more relaxing than to think about that there is a place to go and relax, right? City life is strained（紧张的）, but you can escape this situation and be in the place where there is nothing but relaxation. Here in Durban you will get to see all the amazing tourist attractions（吸引人的地方）. If you love animals and want to see some elephants wandering around the streets, then Durban is the place to go. You can even get to ride one if you want!

    Here you will also get to taste all the delicious South African food. You can choose from Italian cooking to its native dishes. Durban is a great place to tour with your friends and family. You will learn a lot about its history through the landmarks（地标） you will see down the streets. Tourists and even the local villagers just can't get enough of these treats!

    However, it is important that you make the necessary arrangements安排. There are actually lots of tour guides that will help you as you make your journey along the streets of Durban. But if you prefer the best tour guides here in Durban, then you'd better choose the Street Scene Tours. Their staff（员工） are all well­trained and professional（专业的）. They will certainly make your stay here an unforgettable one. No wonder tourists prefer the Street Scene Tours when it comes to Durban City Tours.

    A new study suggests climate conditions in the Sahara Desert, one of hottest, driest and most deserted areas in the world, have changed from wet to dry a about every 20,000 years.

    But previous evidence has suggested the Sahara did not always experience such extreme heat and dry conditions. At times, the Sahara Ranged to a very wet climate. This permitted plants and animals to develop and grow and led to the creation of human settlements. Now, they have discovered more evidence, which, the lead researcher David Mc Gee says, supports the idea that the Sahara's climate kept changing between wet and dry about every 20,000, years.

    McGee reported these climate changes were mainly driven by changes in the Earth's(地轴)as the planet travels round the sun .This process affects the amount of sunlight between seasons. Every 20,000 years the Earth receives more strong summer sunlight. When the Earth's axis changes again, the amount of sunlight is reduced. This season change happened continuously every 20,000 years. The other part of the season produced rainy conditions, resulting in a wetter, greener, plant-rich environment. When the rainy activity weakens, the climate becomes hot and dry, like the Sahara remains today.

    The scientists based their research on dust collected from ocean sediment(沉积物)in the Atlantic Ocean bottom off the coast of West Africa. The dust contained layers (层)of ancient sediment built up over millions of years. Each layer could contain traces of Saharan dust as well as the remains of life forms. This information was used to assess over what time period the dust had built up. This led to the overall finding that the Saharan changes from wet to dry climates happened every 20,000 years.

David McGee said that today we only see the Sahara Desert as an extremely deserted and "inhospitable" place. The new study suggests that the area's climate has changes between grasslands and a much wetter environment, and back to dry climates, even over the last quarter million years. McGee says he thinks the latest research can be valuable in studying the Sahara's history as it relates to human settlement.

    A picture speaks a thousand words. And with over a thousand emoji pictures to represent our words, who needs to speak or write any more? According to Professor Vyv Evans of Bangor University, emoji is the UK's fastest-growing language in history. These little electronic pictures started life in Japanese mobile phones in the 1990s and are now hugely popular. They have inspired fashion, like the real-life dress copied from the dancing lady emoji, and are even recognized as art! In New York's Museum of Modern Art you can now see the first set of the 176 original emojis.

    Why do we love them so much? They allow us to personalize text and have fun as we express ourselves, make people laugh and be creative in how we use them. UK teenagers also told us they really appreciated the fact that emojis are quick and easy.

    People have their favourite emojis. In the UK, the most used emojis are ' face with tears ofjoy', ' face blowing a kiss' and 'Iove heart'. Maybe (with emojis at least) the British are more fun and romantic than people think! Companies such as McDonalds have also tried to use people's love of emojis to make advertisement. They used a series of emojis to tell a story of a disappointing day given a happy ending by a visit to McDonalds. Unluckily for McDonalds, most people added the vomiting(呕吐) emoji to the blank space after the story.

    What is the future of emoji? Is emoji developing so rapidly that it will soon compete with English as a global language? Or is technology changing so fast that emoji will soon be forgotten when the next big thing comes along? It is hard to say and even technology and language experts are divided on the subject.

    What do you think? Keep your eyes open for new developments!

    Breathing dirty air comes at a high price. Air pollution lowers the average life spans (寿命) by a year worldwide and in more polluted parts of Asia and Africa, dirty air shortens lives up to twice that much. Scientists shared their new findings in Environmental Science & Technology Letters. The study used data gathered in 2016 as part of a project known as the Global Burden of Disease and was the first major country-by-country look at the connection between the length of life and what's known as fine PM.

    Air pollution has been linked to many health problems. Most earlier studies had looked at how tiny air pollutants affected rates of illness or death. Joshua Apte is an environmental scientist at the University of Texas at Austin. By looking at life expectancy (预期寿命), his team had hoped to make the threat easier to understand. PM2.5 is what scientists call tiny particles (颗粒) of pollution in the air. Higher levels of PM2.5 can cause health problems and cut months, if not years, from the average length of life. This analysis shows how pollution affects life expectancy in different parts of the world.

    The World Health Organization (WHO) recommends limiting PM2.5 to 10 micrograms per cubic meter of air. Apte's group calculated how holding pollution to this low level would help people. In countries with very dirty air, meeting this standard would lengthen people's lives. However, in countries whose air already meets this standard, the study shows no gain in life expectancy. In other words, meeting the WHO standard won't reduce health costs resulting from dirty air because even below 10 micrograms per cubic meter, pollution still causes serious risks. Meanwhile, the scientists compared how other threats including smoking and cancer shorten the length of life across the globe.

    For 63 percent of Americans, coffee is one of their daily essentials. This number has been this high since 2017, according to the National Coffee Association. The rise of coffee is due to its numerous benefits like preventing DNA damage, but it works best if you do this simple thing first: Eat.

    "Drinking coffee on an empty stomach, or early in the morning before you've had breakfast, can raise the level of cortisol (皮质醇) in your body. From the moment you open your eyes in the morning, your body starts releasing cortisol. It's a hormone (激素) that's responsible for ruling your immune response, metabolism (新陈代谢), and stress response," says Dr. Nikola Djordjevic, MD.

    "If you pump your body with caffeine(咖啡因) when your cortisol is at its peak," Djordjevic says, "you'll be forcing your body to bear even more stress." In a study that evaluated preference for caffeinated drinks among medical students, it's shown that 25 percent of students drank coffee in the morning on an empty stomach.

    These students are at an increased risk of mood changes and possible long-term effects on their health, as explained in the study. "Drinking coffee on an empty stomach can greatly encourage the acid in your stomach, producing a more acidic environment," says Dr. Jamie Long, a licensed clinical psychologist. Thus, a full stomach is important to control the amount of stomach acid produced.

    Since coffee increases your stomach acid, you're highly likely to experience heartburn and even develop gastric ulcers (胃溃疡), Djordjevic says. Clearly, drinking coffee on an empty stomach affects physical health. But it does harm to mental health, too. The overproduction of acid in the stomach can cause mood swings, nervousness, shaking and other withdrawal symptoms (症状). "And if you've already had the sign of experiencing anxiety, you're even more possible to be attacked by the effects of coffee," says Long.

    Base line: Know your limits so you can fully experience what coffee can offer, because here's exactly what happens to your body when you drink coffee daily.