Whether it is “women and children first” or “every man for himself” in a shipwreck may depend on how long it takes the ship to sink, researchers said recently.

When the Lusitania was torpedoed (用鱼雷袭击) by a German ship in 1915, it sank in 18 minutes and the majority of the survivors were young men and women who responded immediately to their powerful survival instincts.

But when the Titanic struck an iceberg in 1912, it took three hours to go down, allowing time for more civilized instincts to take control — and the majority of the survivors were women, children and people with young children.

Economist Benno Torgler of the Queensland University of Technology in Australia and his colleagues studied the two sinkings in order to explore the economic theory that people generally behave in a “rational” and selfish manner. The two tragedies provided a “natural experiment” for testing the idea, because the passengers on the two ships were quite similar in terms of gender and wealth.

The major difference was how long it took the ships to sink. They suggested that when people have little time to react, instincts may rule. When more time is available, social influences play a bigger role. But psychologists noted that many factors other than following social norms (社会规范) could come into play in a disaster, including an evolutionary urge to save the species, attachments that are formed between individuals during the event and the leadership of authority figures.

The extent of altruism (利他主义) and how it occurs “is a very controversial issue,” said Anthony R. Mawson, a professor of preventive medicine at the University of Mississippi Medical Center. He thinks the dominant response was attachment behavior.

Psychologist Daniel Kruger of the University of Michigan, US thinks that the answer lies less in social norms and more in our evolutionary heritage. Human beings have a deep instinct to preserve our kind, he said, and that means “people are more likely to save those who have higher reproductive value, namely the young and women in child-bearing years”.

Kruger also stressed the importance of leadership during a disaster, noting that the Titanic’s captain appeared to have greater control than the Lusitania’s.

Researchers found that sleep deprivation（剥夺）has something with overeating. They studied 17 healthy men and women for 11 days and nights in a lab, where researchers recorded their every movement and recorded everything they ate. That way, researchers could make calculations of how much energy the participants were taking in and how much they were burning off through activities.

After a three-day baseline period, one group was freely assigned to sleep and wake whenever they wanted for eight days, while another was woken up after only two-thirds of their usual sleep time—that amounted to about 80 minutes less sleep per night on average. The group that experienced such restricted sleep tended to eat more the following day, adding 549 extra calories to their usual diet, while those who slept as much as they wanted ate about the same on each of the eight experiment days as they did during the three-day baseline period.

The poorly sleeping group was likely to gain weight over the long term, if their sleep was continually restricted, since they didn't burn any more calories than their better sleeping counterparts. That may help explain why previous studies have found that shift workers who work at night and sleep during the day tend to gain more weight than day workers: their disturbed sleep pattern may enhance them to eat more while they don't expend any more energy to work off the added calories.

Therefore, it's important for people to remember that the relationship between sleep, eating and weight is a complex one. Getting a sufficient amount of sleep each night may play an important role in regulating how much we eat and how many calories we burn, and it may also help determine when we eat. Eating when we should be sleeping may increase the risk of weight gain, as the body is more likely to turn nighttime calories into fat rather than burning them off.

As the cooler days of autumn arrive in the northern part of the world, people are clearing out old plants and planning new gardens for next year. 【小题1】

If the plants have gotten larger than their original containers during their time outside, you can replant them into larger ones. 【小题2】 And replant them with fresh potting soil, and then water them. If you are having trouble removing the plants from their containers, or pots, check to see if the roots have come through the drainage holes at the bottom of the pot. If they have, gently pull or cut the extra roots to help remove the plant.

You can then divide plants like spider plants and flamingo flowers into two or more individual plants. Firstly, shake off any extra soil carefully. Secondly, find the connection between the root system and the plant’s top growth and pull apart the roots gently. 【小题3】 Be sure that there are at least three healthy leaves attached to the root system of each new plant. Lastly, place each new plant in its container. Be sure to use fresh soil mix. Water the plants well until new plants form.

All the house plants that spent summer days outside should be moved to a shady area for a week before going inside for the winter season. 【小题4】 Continue to water regularly during this time.

After a week, look for insects on the plant, especially under the leaves. 【小题5】 If you are still worried about insects, you can spray the plants with Neem oil mixed with water. And complete the move inside before temperatures drop below 12.7 degrees Celsius.