【推荐1】Earthquake can strike without warning. But many injuries and deaths from this kind of natural disaster can be prevented if people follow these safety tips.

If you’re inside a building, stay there! One of the most dangerous things to do in an earthquake is to try to leave a building. But do remember: do it carefully.     1     So do it as follows: Drop to the ground. Get under an object (物体) that is not easily damaged. Hold on to it until the shaking stops. You can also get to a corner formed by two walls with your arms over your hand. If you’re in bed when the quake hits, stay there and protect your head with a pillow.

    2     You can go to the park, playground or fields near your house. Don’t take shelter under a tree, streetlights, electric poles or tall buildings. If you are driving, stop as quickly as possible and stay away from overpasses, buildings, bridges or anything else that might fall or collapse beneath you     3    

If you are trapped in ruins, cover your mouth with a handkerchief or a piece of clothing. Use your cell phone to call for help if possible. Don’t shout.     4     Tap (敲) on a pipe or the wall so rescuers can find you.

Be prepared for aftershocks.     5     However, sometimes they even happen months later. Therefore, if you are not in a safe position (位置) after the first shock, you should move quickly but carefully to a safer place.

【推荐2】Extreme heat often brings extreme wildfires, and this year is no exception, with unprecedented heat waves fueling enormous outbreaks of fires in the western United States and Canada, as well as across the Mediterranean and in Siberia. But paradoxically, the most intense wildfires can have the opposite effect on temperatures, cooling Earth’s surface both regionally and globally.

Thick wildfire smoke can temporarily block sunlight near the ground, causing regional temperatures to drop by several degrees. Wildfire smoke can also have global cooling effects by making clouds in the lower atmosphere more reflective or blocking sunlight in the upper atmosphere, similar to what a volcanic eruption does.

The effect is far too small to counteract human-caused global warming; researchers say it’s too early to predict what it means for the broader climate system. But with fire seasons growing more intense around the world and triggering a range of extreme fire weather in North America and elsewhere, the search for answers is growing increasingly urgent.

Smoke particles act as seeds for water vapor to form clouds that are smaller and reflect more sunlight. While smoke tends to rain out of clouds fairly quickly, the Australian bushfires raged for months, pumping more and more cloud-brightening smoke into the atmosphere. “It’s not a big effect, but when you integrate over the entire Southern Ocean, it adds up,” one of the researchers says.

While this research highlights the cooling effects of smoke in the lower atmosphere, on occasion, wildfire smoke can reach even higher altitudes into the stratosphere, the layer that starts about 10 miles up. There, it can have additional effects on the climate. Smoke reaches the stratosphere when heat from a powerful wildfire creates an updraft that combines with moisture in the atmosphere to generate towering thunderclouds.

However, scientists have only recently begun studying these effects. “We might still be in the infancy of understanding how large and how important the effects of these wildfires are,” scientists say.

【推荐1】Every few years, snowshoe hare (白靴兔) numbers in the Canadian Yukon climb to a peak. As hare populations increase, so do those of their predators (捕食者): lynxes and coyotes. Then hare populations fall and their predators start to die off. The cycle is a famous phenomenon among ecologists and has been studied since the 1920s.

In recent years, though, researchers have found hare numbers fall from their peak not just because predators eat too many of them. Long-lasting stress from living surrounded by killers causes mother hares to eat less food and bear fewer babies. The trauma (创伤) of living through such threats causes lasting changes in brain chemistry, keeping the hares from reproducing at normal levels.

And it’s not just snowshoe hares, as behavioral ecologists Liana Zanette and Michael Clinchy, who study what they call the ecology of fear, have shown. They’ve found that fear of predators can cause other wild mammals (哺乳动物) and songbirds to bear and raise fewer young. The offspring of frightened voles and song sparrows are less likely to succeed in reproducing. These findings add to a growing body of evidence showing that fearful experiences can have long-lasting effects on wildlife and suggesting that post-traumatic stress disorder (PTSD) is not only unique to humans, but shared among other creatures.

Rudy Boonstra, a population ecologist at the University of Toronto, sees the response of snowshoe hares as an adaptation that allows the animals to make the best of a bad situation. Animals stressed by many predators spend more time hiding and less time feeding, so they produce fewer young but that may allow more adult hares to survive to rebuild the population when the cycle starts again.

Despite the evidence that a wide range of animals experience the long-term impacts of extreme stress, some psychologists still hold their human-centric(以人为本的) view of PTSD. “It is defined in terms of human responses,” says neurobiologist David Diamond. “There is no biological measure - you can’t get a blood test that says someone has PTSD. This is a psychological disease, and that’s why I call it a human disorder. Because a rat can’t tell you how it feels.”

【推荐3】Have you ever wondered when dogs first became “man’s best friend” and the world’s favourite pet? If you have then you’re not alone. When and where dogs first began living side-by-side with humans are questions that have stirred hot debate among scientists. There are a few hard facts that all agree on. These include that dogs were once wolves and they were the first animal to be domesticated (驯养) by humans. They came to life some 15, 000 years ago, before the dawn of agriculture.

Beyond that, there is little agreement. The earliest bones found that are unquestionable dogs and not wolves date from 14,000 years ago. However, 30,000-year-old skulls (头骨) have been discovered in France and Belgium that are not pure wolves and that some scientists think could be dogs.

With such puzzling evidence, many scientists are now turning to DNA to find out when and where dogs were first domesticated. In one research project, tens of thousands of blood samples have been taken from street dogs around the world. The plan is to compare them with those of wolves. It’s even possible to analyse DNA from ancient bones. Tiny pieces of the 30,000-year-old skulls mentioned earlier are currently being studied, and another DNA study has already shown that ancient dogs preserved in the Alaskan ice fields evolved (进化) from Asian wolves, not American ones.

Indeed, the ancient DNA may turn out to be more informative than the DNA of living dogs. Because dogs have accompanied humans around the world for thousands of years, their current distribution may tell us very little of their origins. This is why different groups of scientists believe that dogs variously originated in eastern Asia, Mongolia, Siberia, Europe or Africa.

But why were the animals domesticated in the first place? The most recent theory is that dogs domesticated themselves, originally living in and around our ancient villages to eat any food thrown out. Today, this is a way of life still shared by three quarters of a billion unowned dogs worldwide.

【推荐3】The city of San Francisco is a wonderful tourist attraction that offers many different things to see and do. The best way for a traveler to get a good look at the city is to take one of the many different tours there.

Tour the City on Foot

When touring the city by walking, you aren’t going to walk much. What’s more, there are far more benefits. This kind of tour allows you to see as many buildings of the city as possible. A tour of the city on foot usually focuses on a more localized neighborhood level, which can be very interesting in a number of different ways.

Hit the Waters of San Francisco Bay

The Waters of San Francisco Bay have played an important role in the city’s development over the last century, Touring San Francisco from the water is a completely unique way for you to see this wonderful city.

Take a Bus Tour

If you want to see a wide variety of attractions from all over the city, one of the best things you could do is to book a tour through our company that offers services here. A bus tour of San Francisco is one of the most complete ways to experience the city

Tour San Francisco From the Air

While it is one of the most expensive ways to see San Francisco, touring the city from the air is one of the most unique and thrilling ways to see the city. Seeing the city from high above allows you to get a full view of the city as tour guides point out attractions from high above. If you do decide to tour San Francisco by air, you’ll be creating memories that you won’t forget forever.

We are a travel agency providing high-quality services and discounts. For more information, please click here.

【推荐1】When you can’t get away, your kids still can by taking a virtual (虚拟的) field trip to a museum farm, zoo or another fun location. This is a great way to get them interested and happy.

Best Tours of the World: AirPano

AirPano has a variety of tours in China, Portugal, Switzerland and more countries. It offers narrations (叙述) of several tours and includes short written information that’s easy for kids of most ages to read. The tours are also fairly short, which makes these tours great for younger kids.

Best Virtual Dairy Farm Tour: Will-O-Crest Farm

This 45-minule tour of Will-O-Crest Farm in New York state walks through every step of working on a dairy farm. It shows how cows are housed and how cows are milked. The video is hosted by a narrator with a live instructor from the farm onsite.

Best Aquarium Virtual Tour: National Aquarium

The aquarium has more than 20,000 water animals. Kids can click and drag (拖) images to navigate (导航) their way around and use the map to explore various exhibits. Explore eight areas, such as the Amazon River, a rain forest and the Mexican gulf.

Best Natural History Tour: Smithsonian National Museum of Natural History

This museum helps understand nature and humanity's place in it. There's so much to see that not all can be listed here. However, the museum offers an online tour of most of its exhibits. Divide this tour up into a lot of lessons, so kids don't get stressed.

【推荐2】Research carried out last year stressed the growing challenge facing employers in terms of managing and supporting the UK’s aging workforce.

Figures from the Office for National Statistics have suggested that the number of people aged 65 and over still working has reached 1.19 million—up 25,000 from a year ago. There were also now more people aged 50-74 in work than ever before. However, the overall trend was hiding the fact that 12% people are forced to stop working before reaching state pension age because of ill health or disability.

Nearly half a million (436,000) workers who are within five years of state pension age have had to leave work for medical reasons, with an apparent divide between the North (worse) and South (better). Those in the lowest-paid jobs, including cleaners, leisure industry workers and people doing heavy laboring jobs, were twice as likely to stop working before retirement age, because of sickness and disability than managers or professionals.

Within this, the needs of the “sandwich generation”— those juggling work with caring for elderly dependents as well as children — needed to be given greater priority (优先权) by employers, a white paper by insurer and health care provider concluded.

Its research argued that 66% of managers think the average age of retirement in their organization will increase in the next 5 to 10 years. Yet, 36% reported being unaware of anything their organization did to attract, keep and engage older staff. Fewer than a quarter (23%) of employees said they felt supported by their employer with their responsibilities for caring for a loved one.

This was perhaps unsurprising, given that only 28% of managers said their organization had formal policies and practices in place to support these employees, argues health care distribution director Chris Horlick.

【推荐3】Throughout history, people have always been surprised at the intelligence of some birds. Crows(乌鸦)are such an example. Crows’ brain is only about the size of a human thumb, so how smart could they be?

While a crow’s brain may seem small compared with a human brain, what matters is the size of the brain in relation to the size of the animal. According to Professor John Marzluff at the University of Washington’s Aviation Conservation Lab, a crow is actually a flying monkey. Whether it is a friendly monkey or more like a bad one in The Wizard of Oz depends a lot on what you have done to it(or any of its friends).

Can you tell one crow from another? In this way, a crow may be smarter than you because it can recognize human faces. Marzluff’s team caught some crows, made marks on them and released them. Members of the team wore different masks. Crows would attack people wearing a mask, but only if the mask had been worn by someone who had troubled them.

If you think two crows that are watching you and crying to each other are talking about you, you are probably right. In Marzluff’s study, even crows that were never caught attacked scientists. How did the crows describe their attackers to other crows? Their communication is poorly understood. The intensity(强度), rhythm, and lasting time of crying seem to form the basis of a possible language. It turns out that crows can pass on anger to their children-even the little crows attacked masked scientists.

Another case about crows’ great memory comes from Chatham, Ontarrio. Around half a million crows would stop in Chatham during their regular travel, putting the farming community’s crops in danger. Head of the town declared war(宣战)on crows and the hunt began. Since then, the crows have, when passing Chatham, flown high enough to avoid being shot. However, this didn’t stop them from leaving droppings all over the town.