A recent study published in the journal Nature has revealed that our Medieval ancestors left us with a biological legacy: Genes that may have helped them survive the Black Death make us more vulnerable to certain diseases today.

Barreiro and his colleagues examined ancient DNA samples from the bones of more than 200 people from London and Denmark who died over about 100 years that stretched before, during, and after the Black Death swept through that region.

They identified four genes that, depending on the variant, either protected against or increased vulnerability(易损性)to the bacteria that causes bubonic plague(腺鼠疫). They found that what helped people in Medieval times led to problems generations later — raising the frequency of mutations(突变) harmful in modern times. Some of the same genetic variants identified as protective against the plague are associated with certain autoimmune disorders, such as Crohn’s disease. In these sorts of diseases, the immune system that defends the body against disease and infection attacks the body’s own healthy tissues.

Past research has also sought to examine how the Black Death affected the human genome. But Barreiro said he believes theirs is the first demonstration that the Black Death was important to the evolution of the human immune system. One unique aspect of the study, he said, was to focus on a narrow time window around the event. It’s extremely sophisticated and addresses important issues, such as how the same version of a gene can protect people from a horrific infection and also put modern people at risk for other illnesses.

All of this begs the question: Will the COVID-19 pandemic have a big impact on human evolution? Barreiro said he doesn’t think so because the death rate is so much lower and the majority of people who have died had already had children. In the future, however, he said more deadly pandemics may well continue to shape us at the most basic level. “It’s not going to stop. It’s going to keep going for sure.”

Panic attacks are sudden, intense surges of fear, panic, or anxiety. 【小题1】 Panic attacks are generally brief, lasting less than 10 minutes, although some of the symptoms may persist for a longer time. Here are a few tips for you to cope with panic attacks.

Deep breathing

If you’re able to control your breathing, you’re less likely to experience the hyperventilating(呼吸急促) that can make other symptoms — and the panic attack itself — worse. Focus on taking deep breaths in and out through your mouth, feeling the air slowly fill your chest and belly and then slowly leave them again. 【小题2】

Close your eyes

Some panic attacks come from triggers(触发物) that overwhelm you. If you are in a fast-paced environment with a lot of stimuli(刺激), this can feed your panic attack. 【小题3】 This can block out any extra stimuli and make it easier to focus on your breathing.

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Mindfulness can help ground you in the reality of what is around you. Since panic attacks can cause a feeling of separation from reality, this can combat your panic attack as it is approaching or actually happening.

Use muscle relaxation techniques

Much like deep breathing, muscle relaxation techniques can help stop your panic attack in its tracks by controlling your body’s response as much as possible. Consciously relax one muscle at a time. 【小题5】 Techniques of this kind will be most effective when you have practised them beforehand.

Symptoms of Dehydration (脱水)

You’re bad-tempered.

Researchers tested the mood and concentration of 25 women who drank healthy amounts of water one day, and then less the next two days. When slightly dehydrated, the women reported tiredness, bad temper, headaches and difficulty in focusing. In a separate test, men with mild dehydration also had trouble with mental tasks. 【小题1】 Scientists are still trying to figure out why.

You have a bad workout.

【小题2】 It impacts how much you can push yourself. Even a 2 to 3 percent fluid loss affects your ability to get a good workout and more than 5 percent dehydration decreases exercise capacity by about 30 percent.

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Driving while you’re dehydrated may be just as dangerous as getting behind the wheel drunk, in terms of how many mistakes you could make on the road. British researchers had participants take 2-hour drives using a simulator (模拟器). When they drank enough water, there were 47 driving errors. 【小题4】

You feel dizzy when you stand up too fast.

Dehydration can make you feel dizzy or faint, or bring on that rush of light-headedness after you quickly get up from sitting or lying down.

The exact treatment for dehydration symptoms depends on age and how severely dehydrated someone is. 【小题5】 Most of the time, however, people use some over-the-counter solutions for kids, and adults can drink more water.