Although it started as a produce market, the Covent Garden shopping area in London is now filled withmany interesting shops.__21__ in 1661, Covent Garden soon became the market for London and thecountry’s southeast, and all the main shops and restaurants bought their fruits, flowers, and vegetablesthere. In the 1920s, __22__ , Covent Garden’s market closed. For many years, the large warehouse andsurrounding areas remained__23__ . Then, in the 1960s, new shops began to open. By the 1980s, the largemarket building__ 24__ a shopping center. Today, many stores sell fashionable clothing, perfumes, books,and gifts for the home. These stores__25__ inside the original market building and along the streetsnearby. Once again, Covent Garden is a popular shopping area.

       Is there any immortal creature in the world? Despite only being only three millimeters in diameter on average, adult versions of immortal jellyfish (Turritopsis dohrnii) have a huge party trick: they can roll back their biological clock when injured or on the verge of starvation. This means, in theory, they could live forever. Could humans harness their abilities to eradicate ageing completely?

       As scientists have known, the reason of human ageing is a process called trans-differentiation. “This is about how a fully formed specialized adult cell can become another type of specialized adult cell. It’s how a cell can adapt,” explains Dr. Maria Pia Miglietta. The exact mechanism behind trans-differentiation is still a mystery to scientists. However, as Miglietta explains, the answer will likely be found in the jellyfish’s genes. “It most certainly has something to do with the DNA,” she says. “It’s the DNA that programs a cell––certain genes being ‘turned on’ or ‘off’ will determine what sort of cell it is. We’re far away from any kind of real-world application,” says Miglietta. “But we hope that studying what happens in these jellyfish can tell us how their genes change cells––and how these changed cells integrate with others. This is the base of understanding cellular regeneration and tissue regeneration.” 

      However, there are many challenges. These jellyfish have only been studied sporadically since the early 1980s, meaning experts have only a few decades’ worth of data. While an immortal jellyfish can age in reverse, it can also be easily killed by predators including various fish, sharks, turtles and even other jellyfish. “They’re incredibly sensitive, from the water temperature to their plankton and fish egg diet,” says Miglietta. “The real paradox is they’re actually really hard to keep alive!”

        When he moved from South Africa to New York City, Norman Rosenthal, a psychiatrist, noticed he felt more depressed during the cold, short days of the city’s winters than he had in his home country. Years later, he published the first paper to scientifically name the winter blues: Seasonal Affective Disorder (SAD). Subsequent studies have found that the seasonal depression affects those in northern latitudes more and that about 10 percent of SAD sufferers have symptoms in the summertime instead.          The most commonly reported symptoms of winter depression are hypersomnia, the desire to sleep more than usual, as well as an increased appetite and lack of interest in things. According to experts, most people experience symptoms in young adulthood, but SAD can begin at any stage of life. The condition also varies by sex. About three times as many women as men get SAD.

       But why does less daylight make some people clinically depressed? One leading theory is that the change in daylight disrupts our bodies' release of melatonin, a hormone the brain releases every night to promote sleep. As the supply of daylight dwindles in winter, melatonin may wear off later. That means in the morning the body is still in a state of biological night. As for summer SAD, triggers might include the heat and humidity. Instead of feeling lethargic, summer SAD patients more often feel irritable and agitated.

       Experts say a professional diagnosis is a crucial first step toward treatment and self-diagnosis is not suggested. One common treatment is sitting in front of a bright box of light for 30 minutes to signal to the body that it’s time to wake up. But the drawback to light boxes is that they only work on the day that you use them, so you need to use them daily. Another treatment that may have longer lasting benefits is Cognitive Behavioral Therapy (CBT), a form of talk therapy. As negative thinking tends to breed negative emotions, CBT aims to encourage more neutral thoughts. For example, “I hate winter” might be reframed as “winter isn’t my favorite season, but I still find things to enjoy.” Moreover, finding wintertime hobbies may also help. People with SAD often have hobbies that are summer specific, such as growing gardens or beach going. Instead of hibernating under a blanket, people are encouraged to find indoor hobbies, such as knitting, reading, or going to the gym, to boost their mood. Whether using light or talk therapy, there is no reason to not seek mental health treatment, even if symptoms are only present for a few months out of the year.