Working at a desk all day may not be as bad for your health as siting in front of a television after work. That is a finding of a new study done in the United States. It also suggests that not all forms of sitting are equally bad.

Jeanette Garcia works as a researcher at the University of Central Florida in Orlando and she led the study. “We’ve been hearing more and more about how sitting is the new smoking.” she said. She added that other evidence suggests a relationship between health problems and time spent sitting.

“However, it’s been unclear whether all sitting is created equal, suggesting that as long as you reduce any type of sitting, then that’s helpful in improving health,” she added.

“This study suggests that this may not be the case, and that we should focus more on leisure time sitting, mainly television viewing time, rather than other sitting, in general.”

The study followed close to 3,600 African-American adults. Almost one-third of them watched TV for more than four hours a day. A little more than one-third of the subjects spent between two and four hours a day sitting in front of the TV. The remaining third watched TV for less than two hours a day. Researchers followed the group for an average of 8.4 years. During the study, 205 of the subjects died and 129 others suffered a heart attack or stroke (中风).

Compared to people who watched less than two hours of television daily, those who spent more than four hours in front of the TV were 49 percent more likely to die or have a heart attack or stroke.

But the undesirable health effects of watching TV appeared to be limited to adults who failed to get the recommended amount of weekly exercise. That is around 150 minutes of mild physical activity or 75minutes of strong exercise every week.

The study had some limitations, however. Lin Yang, another researcher, says that sitting in front of the TV might be worse than siting at a desk because people snack while watching TV. Some people simply stay up too late and do not get enough sleep.

“Eating treats or lack of sleep could both cause weight gain and increase risk factors for heart disease. These factors could make people more likely to die early,” she added.

The Colorado National Monument, a national park, is an area of great extremes. The ground rises very sharply from the surrounding flat desert area. At first, it seems to be nothing more than huge and very colorful rocks shaped by nature. But if you spend a few hours walking slowly on its many paths, you soon learn that it is very much alive.

Scientists have found seashells high in these mountains and the fossils (化石) of ancient ocean creatures. Near the Colorado National Park researchers have found the huge fossils of ancient reptiles (爬行动物) called dinosaurs (恐龙). One fossil found early last century was the largest fossil dinosaur ever found at that time.

It was huge and it surprised scientists around the world. Scientists are still busy looking for remains of these creatures that died millions of years ago. However, not all of the animals found in or near the park are fossils. Because the area is desert, it is easy to believe that nothing is living here. But if you are very quiet and stay very still, you can see much life in the park. Mountain lions live here. It is very difficult to see them. However, visitors sometimes see the foot marks these big cats left in the soft sand.

If you look closely, you can see small rabbits searching for food or water early in the morning. On hot days you might see deer resting in the shade of trees. The deer are protected from hunters. Often they show little fear of people. Visitors must be careful not to surprise a small reptile called the rattlesnake. The bite of this snake can be very painful and make the injured sick.

Roughly 100 m farmers in several tropical countries depend on coffee for their livelihoods. Unfortunately for them, and for the many other coffee drinkers around the world, coffee bushes grow best in a rather narrow range of temperatures, so their cultivation is threatened by a changing climate. But a chance discovery by Aaron Davis of the Royal Botanic Gardens, Kew, in Britain, published in Nature Plants, may offer a way out. Dr Davis and his colleagues report that they have tracked down a type of wild coffee which is both pleasant to taste and tolerant of higher temperatures.

The existing coffee market is dominated by Coffea arabica and Coffea canephora. Coffea arabica prefers temperatures of 18-22 °C. Recent work suggests that Coffea canephora does not flourish above 24 °C.

Many other coffee species, indeed, grow in places warmer than those preferred by canephora and arabica. But all were thought to have poorer flavours, smaller beans and lower yields. Dr Davis, however, came across a paper written in 1834 by George Don, a Scottish botanist, which described a species from the lowland hills of Sierra Leone. Don dubbed（给……起绰号）it Coffea stenophylla, and wrote that it had a flavour superior to arabica's.

This piqued Dr Davis's interest, for stenophylla still grows, he discovered, in parts of Guinea, Sierra Leone and Ivory Coast that have temperature ranges between 24 and 26 °C. He and his colleagues also learned that stenophylla was farmed up until the 1920s, after which canephora, which had higher yields, took over. Stenophylla was then gradually forgotten.

That history of previous cultivation did, however, suggest stenophylla was worth looking into. The crucial question was Don's praise for its flavour justified? To find out, Dr Davis arranged a competition involving 18 professional coffee tasters who assessed, in a blind comparison, a set of samples that included stenophylla, two types of arabica and one of canephora.

Stenophylla performed well. It was rated as having higher fruitlike qualities than a Brazilian arabica and an Indonesian canephora, and also a more favourable acidity and more complex flavour profile, though slightly less of these qualities than an Ethiopian arabica. When asked if what they were tasting was arabica, the judges said "yes" 81% for samples of stenophylla, compared with 98% for the arabica from Ethiopia.

These results suggest that Don's report from 1834 is correct. Stenophylla does taste like arabica. And, crucially, it tolerates higher temperatures than either arabica or canephora. The rediscovery of stenophylla's qualities offers hope not only to coffee growers who might otherwise have had their businesses harmed by rising temperatures, but also to the world's caffeine addicts, who need now worry less about the future supply of their drug of choice.