[*] Radioactivity occurs naturally. The main source comes from natural sources in space, rocks, soil water and even the human body itself. This is called background radiation and levels vary from place to place, though the average dose is fairly constant. The radiation which is of most concern is artificial radiation which results from human activities. Sources of this include the medical use of radioactive materials, fallout and contamination from nuclear bomb tests, discharges from the nuclear industry, and the storage and dumping of radioactive waste. While artificial radiation accounts for a small proportion of the total , its effects can be disproportionate. Some of the radioactive materials discharged by human activity are not found in nature, such as plutonium(钚)while others which are found naturally may be discharged in different physical and chemical forms, allowing them to spread more readily into the environment, or perhaps accumulate in the food-chain. Many of the elements which our bodies need are produced by the nuclear industry as radioactive isotopes or variants. Some of these are released into the environment, for example iodine and carbon, two common elements used by our bodies. Our bodies do not know the difference between an element which is radioactive and one which is not. So radioactive elements can be absorbed into living tissues, bones or the bleed, where they continue to give off radiation. Radioactive strontium behaves like calcium—an essential ingredient in our bones—in our bodies. Strontium deposits in the bones send radioactivity into the bone marrow, where the blood cells are formed, causing leukemia. In most cases, cell death only becomes significant when large numbers of cells are killed, and the effects of cell death therefore only become apparent at comparatively high dose levels. If a damaged cell is able to survive a radiation dose, the situation is different. In many cases the effect of the cell damage may never become apparent. A few malfunctioning cell will not significantly affect an organ where the large majority are still behaving normally. However, if the affected cell is a germ cell within the ovaries or tests, the situation is different. Ionizing radiation can damage DNA, the molecule which acts as the cell’s “instruction book“. If that germ cell later forms a child, all of the child’s cells will carry the same defect. The localized chemical alteration of DNA in a single cell may be expressed as an inherited abnormality in one or many future generations. In the same way that a somatic cell(体细胞)in body tissue is changed in such a way that it or its descendants escape the control processes which normally control cell replication, the group of cells formed may continue to have a selective advantage in growth over surrounding tissue. It may ultimately increase sufficiently in size to form a detectable cancer and in some cases cause death by spreading locally or to other parts of the body, While there is now broad agreement about the effects of high-level radiation, there is controversy over the long-term effect of low-level doses. This is complicated by the length of time it takes for effects to show up, the fact that the populations being studied are small and exact doses are hard to calculate. All that can be said is that predictions made about the effects of a given dose vary. A growing number of scientists point to evidence that there is a disproportionately high risk from low doses of radiation. Others assume a directly proportionate link between the received dose and the risk of cancer for all levels of dose, while there are some/who claim that at low doses there is a disproportionately low level of risk.

[*] Prevailing mythology has it that creativity is the exclusive domain of artists, scientists, and inventors—a giftedness not available to ordinary people going about the business of daily life. Partly as a result, ordinary people often hold the creative person in awe, finding little gradation in genius. It’s either the Sistine Chapel ceiling or nothing. Our awe of creativity is like a dragon that blocks the gate to our personal creativity. We’ve created this dragon to protect ourselves from something worse: the possibility that we might really go for it, do the very utmost we can do—and find people out there who still don’t think it’s good enough and reject not only what we’ve done, but us as individuals. What we need to understand is that by refusing to risk being creative at less than genius levels, we are already rejecting ourselves, passing judgment without evidence. While that judgment mechanism may have served to protect us from censure as children, we as adults no longer need to feel as vulnerable as we did when we were young. What we need to do instead is assume full responsibility for ourselves. In fact, most individual creativity is pretty humble—no Sistine Chapel ceiling, no Beethoven’s Ninth Symphony, just a solution to such a mundane problem as getting the microwave merry-go-round to work by turning it over and using it upside down, or finding a new way home, or writing a silly verse to a friend. All of these are valid examples of creative behaviors, because the doing of them includes an element of newness, novelty, and difference. What’s more, no matter how severely our creativity may have been repressed in the past, it can be reaccessed, stimulated, and developed through life experiences. This is good news not only for the creatively uninformed or uninitiated. The same techniques that can open the creative world to a novice can set off a creative explosion in the adept. Each person’s experience of creativity is so unique and individual that no one can formulate a definition that fits everyone else. However, it does have something in common. Many people think of creativity purely in term of inventiveness, and that is surely part of it. Besides, to strengthen creative ability, you need to apply the idea in some form that enables both the experience itself and your own reaction and others’ to reinforce your performance. As you and others applaud your creative endeavors, you are likely to become more creative. Creativity’s source is the brain—not just one part of the brain, but all of it. Today, this theme song is well established and accepted. Knowing that creativity arises in the brain makes an enormous contribution to our ability to access, stimulate, develop, and apply the process, because it tells us what process we need to follow, and how that process calls on the brain’s specialized capabilities at each stage. A major key—perhaps the key—to living creatively is passion, which means a highly compelling, energetic attention to something. Turned-on people of all kinds are passionate. So are collectors, sports nuts, and boys who’ve just discovered baseball cards or video games, and computer hackers. How do we reclaim our passion if it has been allowed to dim in our lives? One way—an important way—is to increase the amount of genuine pleasure we allow into our lives. There are many things that make life more pleasurable.

[*] A new study suggests that it would be possible to achieve a 25% increase in density in a typical provincial city without changing the traditional street scene, although it would be necessary to reduce the size of the houses and substitute parking spaces for garages. Therefore, the cost of this approach is to have more people living in smaller homes at higher densities, along streets that are lined with parked cars. Can we really accept the notion that space within dwellings may be reduced even further? In times when, we are told, living standards are rising in real terms, is it realistic to seek to reduce personal space standards? The streets of many inner suburbs are already lined with cars on both sides, reducing movement to a single lane. Increasing densities means accepting urban streets that are designed as linear car parks, bounded by even smaller living units and tempered only by occasional streets sprouting from the tarmac. Those without economic choice can be directed to live in this way, but if we are to continue to rely on the private sector to produce this urban housing, it will need to appeal to the private developers’ customers. Who will choose to live in these high-density developments of small dwellings , with minimal open space and a chance to park on the highway if you are lucky enough to find a space? The main consumers will be single people, couples without children, and perhaps some “empty nesters“(people whose children have grown up and left home). These are people who can choose to spend much of their time outside their home, making the most of those urban cultural opportunities or getting away at weekends to a country cottage or sporting activities. The combination of a young family and a mortgage restricts the mobility and spending power of many couples. Most people with a family will try to avoid bringing up their children in a cramped flat or house. Space for independent activity is important in developing the individual and in maintaining family equilibrium. The garden is the secure place where the children can work off excess energy. There is a danger that planners may take a dispassionate, logical view of how we should live, and seek to force society into that mould. A few years ago a European Commission study provided a good example of this. It took the view, quite sensibly, that housing should not be under-occupied because this is a waste of resources. Therefore, it would be much better if the many thousands of old ladies who live alone in large detached houses would move into small urban flats, thus releasing the large houses for families. What the study failed to recognize was that many of those old ladies prefer to continue to live in their family home with their familiar surroundings and, most importantly, with their memories. What is good for us is not necessarily what we want. The urban housing option may be technically sustainable, but individually unacceptable. There still seems to be a perception among planners that new housing investment can be forced into those areas that planners want to see developed, without proper consideration of where the prospective purchasers want to live. There is a fatal flaw in this premise. Housing developers run businesses. They are not irrevocably committed to building houses and they are not obliged to invest their resources in housing development. Unless there is a reasonable prospect of a profit on the capital at risk in a housing project, they may simply choose to invest in some other activity.

[*] I want to talk about the economy, not the one we hear about endlessly in the news each day and in politicians’ speeches, but the one we live in day by day. It’s where most of us live on a daily basis, earning our living, paying our taxes, and purchasing the necessities of life. The term “economic expansion“ suggests something desirable and benevolent, but expansion simply means spending more money. More spending doesn’t mean that life is getting better. More spending merely feeds our whole economic system, which is based on production and consumption. Unless money keeps circulating, the economy collapses. If we don’t keep consuming, then manufacturers and retailers go out of business. As a leading economist put it, consumer societies are “in need of need“. We don’t need the things the economy produces as much as the economy needs our sense of need for things. Need is the miracle that keeps the engines of expansion turning relentlessly. In economics, there is no concept of enough. It is a hunger that cannot be satisfied. There is so much craziness in the world. There is an American company that manufactures a range of food with a high fat content. This causes obesity and high blood pressure. By coincidence, the same company also makes products that help people who are trying to diet. Not only that, it even produces pills for those with high blood pressure. Nearly all of my mail consists of bills, banks trying to lend me money, catalogues trying to make me spend it, and charity appeals for the losers in this ecstasy of consumption—the homeless, the refugees, the exploited, the starving. Why is it possible to buy strawberries from Ecuador and green beans from Kenya when these countries can hardly feed their own people? It is because there are cash crops, and the countries need the money to service their debts. Notice that servicing a debt does not mean paying it off. It means just paying the interest. Western banks make vast profits from third world debt. We buy clothes that are manufactured in sweat shops by virtual slaves in poor parts of the world. We create mountains of waste. We demand cheap food, mindless of the fact that it is totally devoid of taste and is produced using chemicals that poison the land. We insist on our right to drive our own car wherever we want to go. The evil of the consumption culture is the way it makes us oblivious to the impact of our own behavior. Our main problem is not that we don’t know what to do about it. It is mustering the desire to do it.

Mining operations by their very nature have major impacts, positive and negative, on the local area and on local communities. They are usually in remote places and the people affected are often isolated or neglected communities. [*] It is inevitable that mining operations will disturb the environment in a fairly dramatic way. Forest cover may have to be cut down to clear the site of the mine or for access roads. Tunnels or open-cut pits are dug. Overburden is removed and dumped nearby, usually to erode slowly into nearby streams and rivers. Tailings from the ore processing plant have to be put somewhere—preferably into an on-site tailings dam, but more likely straight into a river or the sea. Mine tailings may contain some dangerous chemicals, but the major problem is usually the huge amounts of solid sediment that they put into the river system, and the effect this has on water quality and marine life. This can directly affect the livelihood of people living down-stream who depend on the river for fish, for drinking water for themselves and their animals, or for cooking or washing. Heavy sedimentation can slit up rivers, making transportation difficult and causing fields and forests by the river banks to flood. Other environmental effects can include air pollution from trucks tearing along dusty access roads, or more seriously, fumes from ore processing plants. Large amounts of cash will normally be injected into the local community in the form of royalties or compensation to landowners, wages to mine workers or payments to sub-contractors. While this can be very beneficial it can also lead to inequalities, disputes and problems. Those in the local community who acquire cash from wages or compensation and the power that goes with it are not necessarily those who by tradition hold power in that society. The very advent of the cash can have a disruptive effect on traditional social structures. Also in societies where resources including cash are owned communally and shared out according to traditional rules and precedents, the injection of very large amounts of money can strain the rules and tempt some to keep more than their entitlement, thus causing internal rifts, disputes and fighting. Disputes between landowners and mining companies over payments or compensation are also common, and can lead to violent reactions against landowners by the police or armed forces, or repression by the authorities. Mining also, of course, brings considerable benefits. Locally it provides jobs and incomes, and for those who use their income wisely, and escape from grinding poverty and a life of hardship and struggle. It also brings development and services such as roads, wharfs, airstrips, stores, health clinics and schools, to areas which are usually remote and often neglected by government. The advent of health care and educational facilities to remote areas that would otherwise not have them can be especially beneficial. Opinions about a mine will usually vary. Those most in favor tend to be those living near the mine and enjoying its facilities, who have been generously compensated for loss of land or damaged environment , or who are earning good money as mine workers or sub-contractors. Among those least in favor will be women living in or near the mining settlements who have to put up with alcoholism, domestic violence , sexual harassment or other social ills, and people living downstream, far enough away from the mine to be receiving little or no compensation but who nevertheless suffer its polluting effects. The environment is greatly influenced by mining operations, whose main problems are solid sediment and its effect on【R1】______. Environmental influences also include flooding, air pollution and fumes. Mining operations will definitely change the social life.【R2】______may get injured by the injection of a great deal of cash, which may result in【R3】______. On the other hand, mining also has positive effects. There may be an obvious increase in job opportunities and incomes. It stimulates the development and promotes services, especially【R4】______for local people. People’s【R5】______on mining depends on whether it does good or harm to them.

The passage covers two kinds of radiation, background radiation and artificial radiation.

When a small group of cells survive a radiation dose, they definitely won’t result in the disability of people.

More and more scientists tend to believe that low doses of radiation may do great harm to people.

In the same way that a somatic cell in body tissue is changed in such a way that it or its descendants escape the control processes which normally control cell replication, the group of cells formed may continue to have a selective advantage in growth over surrounding tissue.