【推荐2】Climate change has increased average temperatures by1degree Celsius over the past century, making heat waves like this one more frequent and intense than those from any other point in recorded history. As the heat soars, so does the death toll. A worldwide study published last month in the journal Nature Climate Change found global warming was responsible for 37% of heat-related deaths between 1991 and 2018. As temperatures tick ever higher, that figure may well rise.

“There’s still a lot we don’t know about heatstroke and who’s most likely to be affected by it,” Kenney said.“That’s because we can’t morally study it in humans in the laboratory. A lot of what we know comes from studies on animal models, like mice and rats, or from examinations of people who have died of heat stroke.”

We are also learning more, about how to avoid overheating. A 2019 study by University of Sydney researcher Ollie Jay found that electric fans cooled body temperatures and reduced cardiovascular (心血管的) strain in hot, humid weather. But in dry heat, fans actually increase body temperature—meaning access to air conditioning is crucial.

But the most likely assurance against dying of extreme heat is preventing the rise of global   temperatures. Last year tied 2016 for the hottest ever recorded worldwide. Despite a brief drop in planet-heating emissions as the COVID-19 pandemic shuttered factories and idled cars, we’re on track to see global temperatures increase this century by about 3 degrees Celsius. Changing that trend requires rapidly and greatly reducing fossil fuel use and finding ways to remove more carbon from the atmosphere than we release. Efforts so far have not been enough. Global oil demand, the Organization of Petroleum Exporting Countries predicted last month, will jump by 5 million barrels per day in the second half of 2022 compared with the first six months.

【推荐3】Tropical(热带的)birds deep in Brazil’s Amazon rainforest are shrinking as the world’s climate changes. Researchers studied data for 77 tropical bird species over the past 40 years and found that all of them had lost body mass, with some species losing nearly 2% of their weight per decade.

A 2019 study of birds that had crashed into buildings in Chicago, Illinois, found that they’d lost mass over a 40—year period, but those species were migratory(迁徙的). However, why the birds changed in that way was unknown. Therefore, researchers decided to examine the records of 15, 000 non-migratory birds living in a rainforest within a few hours’ drive from Manaus in Brazil.

The average temperature of the birds’ habitat is 1℃ warmer in the wet season and 1. 65℃ warmer in the dry season compared with that in 40 years ago. What’s more, 13% more rain falls in the wet season and 15% less in the dry season. The birds have lost mass more sharply following extremely dry or wet seasons. This could be a short-term response to changes in their environment, such as a lack of rainfall causing a decline in the number of insects that the birds feed on.

“Mass is a generally good indication of body condition in birds, says Vitek Jirinec at the Integral Ecology Research Center in California, who led the study. "If they’re simply not getting enough to eat, you’d expect them to lose weight.”

Birds of the same species are generally larger at higher latitudes. The leading theory is that their smaller surface — area — to — volume ratio（表面积和体积比）allows them to better conserve heat. The opposite would help smaller species in hot climates to cool and could explain why birds are getting smaller as the climate warms, says Jirinec.

The marked physical change during just four decades show why stopping destroying trees alone won’t prevent the ongoing extinctions of animal species across the world, says Camila Gomez, a scientist who studies evolutionary changes in birds. "This study also shows how human-caused changes in climate are contributing to observed population declines in tropical birds," says Gomez.

【推荐2】What can you expect when you travel across the UK border? What must you do if you want to travel to the UK? The information here is for all travelers, including the UK Passport holders, residents and short-term visitors.

If you are making a short-term visit to the UK, the sections on visitors’ rights and responsibilities will tell you whether you can do business while you are here, what medical treatment is available to you, and whether you will register with the police.

Section 1: Customs

This section explains what you can bring into the UK, and how to go through customs control at the UK border.

Section 2: Before You Travel

This section explains who needs to apply for permission before travelling to the UK, why we collect information on passengers before they travel to the UK, and the requirements for general airline operators and pilots who want to travel to the UK.

Section 3: Enter the UK

This section explains what happens when you arrive at our border, how to use our IRIS system to enter the UK quickly, and what happens if you are refused to enter it.

Section 4: Transit through the UK

This section explains how you can pass through the UK, when travelling on to another country, describes the “transit without visa” permission and the direct air side visa, and tells you which document you will need.

This page is for visitors to consult and learn about countries around the world. Loads of travel guides can be clicked here!

【推荐3】Too much stress can make it more likely for a person to get sick, and so scientists are trying to think of ways to keep people from being overly stressed. In this experiment, scientists studied the effect of music on stress.

Scientists asked women to either listen to relaxing music, nature sounds, or to nothing. Following the music session, they had the women stand in front of an audience and perform two tasks. First, each woman had to give a speech. Second, each woman had to do complex math in her head. These two tasks make up the Trier Social Stress Task, a method scientists use as a sure-fire way to make people feel stressed.

Scientists know that the body responds to stress by releasing cortisol (皮质醇), and so they used it to measure stress. Scientists compared cortisol levels after listening to music and at various times after doing the Trier Social Stress Task. The scientists also measured an enzyme (酶) called alpha-amylase. Alpha-amylase is important to your body as it kills unwanted bacteria and it helps break down the food that you eat. Alpha-amylase is also released by the nervous system in response to stress.

The scientists tested how classical music and nature sounds affect levels of cortisol and alpha-amylase. The alpha-amylase levels of people who listened to classical music went back to normal more quickly compared to the people listening to nature sounds.

The people listening to relaxing music showed a stress response that was shorter compared to the other groups. The shorter response helps to prevent the body from getting worn out. This means that listening to relaxing music might help to improve the stress response and health.

The results of this study were a bit mixed. Scientists still have a lot of work to do to see if listening to music can reduce stress by lowering cortisol levels in the body. Until we know more, maybe play some tunes or listen to some nature sounds when you feel stressed. Even if it doesn't directly help your stress level, it's still nice to hear a good song.