Suppose you become a leader in an organization. It's very likely that you'll want to have volunteers to help 

with the organization's activities. To do so, it should help to understand why people undertake volunteer work and

what keeps their interest in the work.

       Let's begin with the question of why people volunteer. Researchers have identified several factors that 

motivate people to get involved. For example, people volunteer to express personal values related to unselfishness, 

to expand their range of experiences, and to strengthen social relationships. If volunteer positions do not meet these 

needs, people may not wish to participate. To select volunteers, you may need to understand the motivations of the 

people you wish to attract.

         People also volunteer because they are required to do so. To increase levels of community service, some 

schools have launched compulsory volunteer programs. Unfortunately, these programs can shift people's wish of

participation from an internal factor (e.g., “I volunteer because it's important to me”) to an external factor (e.g., “I

volunteer because I'm required to do so”). When that happens, people become less likely to volunteer in the future.

People must be sensitive to this possibility when they make volunteer activities a must.

          Once people begin to volunteer, what leads them to remain in their positions over time? To answer this 

question, researchers have conducted follow-up studies in which they track volunteers over time. For instance, one 

study followed 238 volunteers in Florida over a year. One of the most important factors that influenced their 

satisfaction as volunteers was the amount of suffering they experienced in their volunteer positions. Although this

result may not surprise you, it leads to important practical advice. The researchers note that attention should be 

given to “training methods that would prepare volunteers for troublesome situations or provide them with 

strategies for coping with the problem they do experience”.

         Another study of 302 volunteers at hospitals in Chicago focused on individual differences in the degree to 

which people view “volunteer” as an important social role. It was assumed that those people for whom the role of 

volunteer was most part of their personal identity would also be most likely to continue volunteer work. 

Participants indicated the degree to which the social role mattered by responding to statements such as 

“Volunteering in Hospital is an important part of who I am.” Consistent with the researchers' expectations, they

found a positive correlation (正相关) between the strength of role identity and the length of time people continued 

to volunteer. These results, once again, lead to concrete advice: “Once an individual begins volunteering, 

continued efforts might focus on developing a volunteer role identity.... Items like T-shirts that allow volunteers to 

be recognized publicly for their contributions can help strengthen role identity”.

    More than 10 years ago, it was difficult to buy a tasty pineapple.The fruits that made it to the UK were green on the outside and, more often than not,hard with an unpleasant taste within.Then in 1966,the Del Monte Gold pineapple produced in Hawaii first hit our shelves.

    The new type of pineapple looked more yellowy-gold than green.It was slightly softer on the outside and had a lot of juice inside.But the most important thing about this new type of pineapple was that it was twice as sweet as the hit-and-miss pineapples we had known. In no time, the Del Monte Gold took the market by storm, rapidly becoming the world's best-selling pineapple variety, and delivering natural levels of sweetness in the mouth,up until then only found in tinned pineapple.

    In nutrition it was all good news too.This nice tasting pineapple contained four times more vitamin C than the old green variety.Nutritionists said that it was not only full of vitamins, but also good against some diseases.People were understandably eager to be able to buy this wonderful fruit.The new type of pineapple was selling fast9 and the Del Monte Gold pineapple rapidly became a fixture in the shopping basket of the healthy eater.

    Seeing the growing market for its winning pineapple, Del Monte tried to keep market to itself.But other fruit companies developed similar pineapples.Del Monte turned to law for help, but failed. Those companies argued successfully that Del Monte's attempts to keep the golden pineapple for itself were just a way to knock them out the market.

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    Scientists think that growing garden grass could be the secret to solving our energy needs, and we may soon be able to replace our gasoline with "grassoline".

    The team, including experts from Cardiff University in Wales, has shown that hydrogen can be taken from grass in useful amounts with the help of sunlight and a cheap catalyst(催化剂) —something that speeds up a chemical reaction without being used up.

    It is the first time that this has been shown and it could lead to a sustainable(可持续的) way of making hydrogen, reported Asian News International. This could be an important kind of renewable energy because it is high in energy and it does not give out harmful gases when it is burned.

    Study co-author Michael Bowker said, "This is really a green source of energy. Hydrogen is seen as an important future energy carrier as the world moves from fossil fuels to renewable energy, and our research has shown that even garden grass could be a good way of getting it."

    Cellulose(纤维素), which is a key part of plants and the biopolymer(生物聚合物) found in the largest numbers on the earth, could be a great source of hydrogen.

In its study, the team looked at the possibility of getting hydrogen from cellulose using sunlight and a simple catalyst.

    This is called photocatalysis(光催化作用) and in it, the sunlight starts the catalyst, which then makes cellulose and water into hydrogen. The researchers studied the effectiveness of three metal-based catalysts, of which nickel(镍) especially interested the researchers, as it is a much more common metal than gold and palladium(钯) and it saves more money.

    According to Bowker, producing hydrogen from cellulose using photocatalysis has not been studied in detail. The team's research shows that large amounts of hydrogen can be produced using this method with the help of a bit of sunlight and a cheap catalyst.

    The study shows that it is effective to use real grass taken from a garden. "This is important as it avoids the need to separate and clean up cellulose, which can be both difficult and costly," said Bowker.

    Guide dogs are going to be available for the children who are unable to see normally in the UK for the first time, as the age limit is to be removed. The Guide Dogs for the Blind Association is to begin training dogs to help blind people under the age of 16.

    The association says too many youngsters with impaired eyesight are lacking in independence. They have only a limited social life because of their disability. Giving some of them guide dogs at a younger age is intended to help them to widen their range of activities and to improve their sense of self-confidence and independence. Guide dogs for these teenagers will begin to be provided from next year. There has been an experimental project to test the use of guide dogs with younger people.

    Charlotte, aged 14, was among the youngest guide dog owners. She had been gradually losing her eyesight since the age of eight, and lost her eyesight completely this year. She has been assisted by a two-year-old guide dog. Charlotte used to have a long stick to help her move around, but having a guide dog allows her much more freedom and makes her feel safer.

    However, the association says there is a worryingly patchy supply of services for the young blind people across the UK, and it calls for a sharp increase in the number of guide dogs all over the country. As with adult blind people, only a small number of them are likely to be considered suitable for a guide dog. Most will continue to rely on extra help and training from education and social services.

    Vinegar is great. It makes salad, fries and dumplings taste better, and you can even clean your windows with it. And now, according to scientists, it may even help the planet's population to ease hunger.

    Researchers from the RIKEN Center for Sustainable Resource Science (CSRS) in Japan found that growing plants in vinegar makes them more resistant to droughts.

    This could mean that in the future, worries about climate change affecting the world's supply of food will be much lower.

    The discovery was made after the researchers studied the Arabidopsis, a plant known for its ability to survive in dry weather. It was found that when the plant was placed in drought-like conditions, it produced a chemical called acetate(醋酸盐) – the main component of vinegar.

    After discovering this, the scientists experimented further by adding acetate to the soil of other plants, before they stopped giving them water completely. After leaving the plants for 14 days, they found that the ones treated with acetate had survived, while the untreated plants had dried up and died. It's hoped that this simple method of survival could soon be used to help farmers in dry countries keep their crops alive.

    Jong Myong Kim, co-author of the study, told Popular Science magazine that he's already been in touch with people all over the world who are interested in trying this simple and cost-effective method out for themselves from flower growing companies to amateur gardeners.

    Although at this point keeping thirsty plants alive isn't as easy as just pouring vinegar over them, Kim said he and his team are working on making the process as simple as possible. "Now we are trying to cooperate with some farmers, and also some companies, to make a method to apply this system." he said.

    And for those of us who always forget to ask our neighbors to water our plants when we go away, hopefully this means the end of returning home from a trip to find our favorite flowers have died.

    City trees grow faster and die younger than trees in rural forestry, a new study finds. Over their lifetimes, then, urban trees will likely absorb less CO₂ from the air than forest trees.

    As we all know, the earth would be freezing or burning hot without CO₂. However, CO₂ is a greenhouse gas, meaning it traps energy from the sun as/heat. That makes temperatures near the ground rise. Human activities, especially the widespread burning-of fossil(化石)fuels, have been sending extra greenhouse gases into the air. This has led to a rise in average temperatures across the globe.

    Studies had shown forests readily absorb CO₂, but there hadn't been much data on whether city trees grow, die and absorb CO₂ at the same rate as forest trees do. So some researchers decided to find out.

    To figure out how quickly trees were growing, researchers tracked their diameters (the width of their trunks) between 2005 and 2014. A tree's diameter increases as it grows, just as a person's waist size increases as they gain weight. About half the weight of a tree is carbon, research has shown. Most of the rest is water. Over the nine years' tracking, the researchers found city trees absorbed four times as much carbon from the air as forest trees. However, they were twice as likely to die. So over the lifetime of each type of tree, forest trees actually absorbed more CO₂.

    City trees grew faster because they had less competition for light from their neighbors. In a forest，trees tend to grow close together，shading their neighbors. Street trees also benefit from higher levels of nitrogen (氮)in rainwater. Nitrogen helps plants grow. Waste gases from gas-burning cars also contain nitrogen, thus enriching city air with nitrogen. Later, rainwater may wash much of it to the ground. Some street trees may also have better access to water than trees in the country because the underground water pipes can leak.