Genetic modified organisms Essay
Genetic modification has become the part of our life. The genetically modified foods, genetically modified animals and even genetically modified people- these are the words heard by us almost every day. The successful development of sciences always creates something profitable and necessary for the Humanity but in the case of genetically modifies organisms (GMO) the human society has to be more than careful. When the genetic material of an organism is altered by the method that doesn’t take place in nature different results could be expected. The techniques of the genetic modification (GM) are applied to practically all alive creatures on our planet, so the question of the relations between original nature-born organisms and its scientific analogies is one of the most important. Manipulating the nature is very attractive for human beings. Changing creatures born by nature, people get the functions of God.
They can change and modify, give new forms and create new formulas of life. But one step made in a wrong way is able to convert human nation into victims of their own activities.GENETIC MODIFICATION: WHAT IF IT GETS INTO NATURALLY MODIFIED WORLD? Today the great quantity of popular and scientific editions write about that dark side that is occulted behind the advantages of the new method of creating alive organisms.
As it is known, each cell of the organism contains long chains of a complex chemical which is called DNA (deoxyribonucleic acid). The GM realizes the removal of DNA , its manipulation outside the cell and reinsertion into the organism which can be the same or another one. The purpose of this actions is to create some new characteristics in the structure of the organism under investigation. The ability to change the genetic structure of the organism is a great step forward. Many extremely useful medicines had been created by GM: blood clotting factor 8, insulin and blood cell growth factors. But the main danger caused by the removal of DNA and interference into the genetic scheme of the organism is that some new undesirable effects may appear. So, why is the Genetic modification so dangerous? Having looked at the enormous benefits we have already seen in agriculture and medicine as a result of genetic engineering, we now need to ask about the possible dangers before then thinking about law changes or other regulations. A transgenic animal is one who has had extra genes from another animal—usually another species—inserted into their genes.
A cloned animal is nearly an exact genetic copy of another animal, usually produced by transferring a cell nucleus from the body of the “parent” to an egg cell. Scientists are applying both these technologies to food animals with the intention of improving production efficiency, product quality, or environmental adaptation. Among the animals being created are dairy goats who have had a rat gene inserted to change the fat composition of their milk to make it more healthy for consumers. There are so-called “Enviropigs” whose genetic structure has been altered so their manure will contain less phosphorus to mitigate environmental degradation. “Self-healing catfish” have a moth gene inserted into their DNA, which enables them to secrete an antibacterial protein that protects them against infections; this is said to improve survival rates by two to four times. Featherless chickens are claimed to be environmentally friendly, lean, and fast growing. Dairy cows of “high genetic merit” are being cloned to increase production.
But all these so-called benefits aren’t so good when the whole picture is examined. The National Academy of Science (NAS) review of this issue, published in September 2002, found that the genetic modification and cloning of animals has negative effects on their welfare. Furthermore, cloning is highly inefficient at this point and provokes high death rates. For those animals born alive, it is evident that they suffer from a large number of abnormalities such as brain lesions, skeletal malformations, and incomplete development of the vascular tract. It is common for cloned calves and sheep produced in vitro to have higher birth weights, often requiring repeated caesarean sections on the same breeder animal. Even when transgenic animals survive, the inserted gene often does not work properly, which can result in a variety of abnormalities. There is also concern that novel products produced in the animal’s milk can leak into other parts of the animal’s body, potentially causing adverse effects. While some of these welfare concerns are not exclusive to biotechnology, their high rate of occurrence and potential to cause suffering means use of the technology should be examines very carefully.
Genetic engineering and cloning of animals to increase production is impossible when current practices of artificial selection have already resulted in a number of production-related diseases in farm animals. These diseases are such as: mastitis and laminitis in dairy cows, skeletal problems in broiler chickens and turkeys, osteoporosis in laying hens, and excitability in pigs. Because they are potentially painful and crippling disorders that affect a large number of animals, they represent a significant animal welfare problem. It is ethically unjustifiable to use a technology that would have such negative results. If this animal gets into wild nature or gives birth to its children , this can’t be compared with the natural process of life. We don’t know what kind of results can be expected, how this gene will behavior in the outspread world.
Though, the idea that life forms such as animals have no intrinsic value can spread. The development of cloning techniques may pave the way for the use of the technology on humans. Already some scientists are claiming that they want to clone a human being.GM PLANTS : ADVANTAGE OR DISASTER? There has been an enormous amount of talks about the risks. We have to be aware of the high risks and responsibility of everybody who is involved in these new systems, especially the scientist who produces genetically engineered organisms. .On a practical level it’s possible to consider some of the things that could go wrong. The idea that an organism could do great damage if released in the wrong place is based on bitter experience.
There were many times where plants introduced from one country into another have unexpectedly become a nuisance. Therefore there is a question what could happen if a genetically altered species were released into the environment with unexpected results . An example is the case about rhododendrons in Snowdonia and other parts of the UK. This plant was imported from India for the first time in the eighteenth century by wealthy landowners who liked the evergreen bushes . The bushes grow very densely, giving a wonderful shadow. They grow tall and then flop over, suffocating nearby plants and young growing trees. They also disturb the balance of the soil, making it more acidic. But we all appreciate country walks through wild woodlands rich with the beauty of these flowers.
The problem is that the plants are too resilient. About 250 different types of insects, fungi, or small creatures live on oak tree. This ecological system maintains a balanced environment and keeps oak trees from dominating the countryside. The rhododendron is an unfriendly plant. The leaves are juicy but unpleasant to eat so even in a deer park they may be left alone. The leaves have really no food value even if they are eaten.
There are very few other creatures that live on rhododendron bushes – no fruits to eat or nuts to collect or sap to drink. The bushes are spreading steadily, escaping from where they were planted out. If they are cut down they just grow up again. As a result in places like Snowdonia they have become a ferocious weed. It is one thing to move a naturally occurring organism from one area to another, but what can happen about introducing an organism the world has never met before –genetically modified organism. This is the question we are to resolve. Now we speak about the effects of new plants created in the laboratory and released into the environment. We are to be sure that a particular cereal plant does not turn into a nuisance.
We are to be sure that a genetically engineered fish does not multiply so fast that other types of fish are died or even eaten by them. There exists a wide range of branches where GM organisms can overcome the limits supposed to preserve the safety. For example, genetically modified trees consist rather a big problem for the environment. Lately, the serious threat of genetic pollution takes place in Latin America and Asia. In the UK five GM tree trials took place but all of them failed after not having passed the test on the environmental impacts on soil, water and wildlife.
In Latin America and Asia despite of its negative influences , GM trees were used. Besides being long living some kinds of GM trees can be spread up to 600km round. As affirms the article “GM trees threaten the global environment(1999) “ : “Since 1988 there have been at least 116 GM tree trials involving 24 species in 17 countries. The late 1990s have seen a huge increase in both the number of GM trials and species tested. In the last three years the number of tree trials has doubled, with 44 new trials in 1998 alone”(n.p.) (Without the author, GM trees…,1999).
Francis Sullivan, Director of one of the environment protective programmes says that(1999) “once the GM genie is out of the bottle there is no going back. This technology must only be used if we are confident that it will not have a negative impact on forests and wildlife and people they support”(n.p.) (Rachel Nowak,1999).
The further development of GM tree trials can cause unintended side effects on the tree and forest eco-system. Being often located GM trees near natural forests the chances of genetic pollution are increasing significantly. It’s not possible to continue the use of GM trials until enough research will be conducted. GM products producers say their technology will help to diminish the use of chemical weed killers. But GM crops themselves causes many new problems. As GM crops are created to have a strong ability to survive, the seeds which are left in the field can germinate in later years when a different crop is growing and can contaminate it. GM crops can themselves act like weeds.
For example, in Canada, GM herbicide-tolerant oilseed rape are grown since 1998 and , consequently, oilseed rape weeds resistant to three different herbicides have been created . This is an example, of so-called “gene-stacking” –when a few GM traits are in the same plant. The Canadian Ministry of agriculture study investigated 11 GM sites and in all of them was found the gene-stacking. Lately, the Bt crops were used- these are to produce the insecticidal toxin. But the practice showed that the pest it was created to control could adopt to Bt within 1-2 years . Besides, it was observed an increase (250-300%) of attacks of non-target pests. Bt corps were dangerous also for some species of insects whose existence is important for eco-system.
Continuing the talk about modified crops it would be superfluous to give the results of the investigation of the New Zealand Royal Commission on Genetic Modification. They investigated a particular engineered bacterium that had been approved for use in the USA. While testing none of the harmful attributes was found. But later, the engineered bacterium( Klebsiella planticola) which contained an alcohol gene killed all the wheat plants in the sites where it was added. The engineered bacterium was producing much more alcohol that it was necessary and could kill any plant. This would cause the death of all terrestrial plants. This case shows that the modern testing procedures are inadequate in clearing up the real level of danger.
GM FOODS: DESEASES IN YOUR PLATE.Everyone has already seen the large range of new foods available and the absence of control mechanisms to ensure safety. Concerning all the negative factors of producing GM crops describes above, it’s not hard to guess that the final product received after the processing of these crops also will contain a number of elements which are dangerous for the human organism. Gm products frequently contain proteins that never consisted the part of the human food chain. So, different kinds of allergic reactions can be caused, especially among children , It means that the products which before had been considered to be safe , became dangerous for people suffering allergy. Gm “Star Link” maize which had been approved for animals was sold for human consumption in the USA. It contained a toxin which is considered to be a human allergen –it can’t be broken down by gastric acid –one of the main characteristics of a wide range of allergens. To identify which plant cells have successfully adopted foreign genes, were created the antibiotic-resistance genes.
In 2002 the study of the UK’s Food Standarts Agency (FSA) cleared up that the antibiotic-resistance gene from GM foods can get into human gut bacteria after one meal only. DNA doesn’t always dissolves in the human alimentary tract. Gut bacteria takes up genes or specific GM components and this gives the possibility of the outbreak of antibiotic resistance.
So, in case of having failed the function of GM gene practically uncontrollable epidemics could appear. BACTERIA OR POTENTIAL KIILER? Speaking about water supplies or soil they are also used in genetic engineering and tampering with the genetic code of a non-soil organism could produce one which was able to survive in the soil quite well, or could turn a harmless soil organism into a global hazard . So here we are to determine if we are producing domesticated bacteria or potential killer? The problem is we aren’t able to know certainly how will the new created gene conduct. We know very little about how genetically engineered bacteria might be carried in a strong wind from, for example, a small crop spraying airplane or helicopter. Microcomputer programmes are developed to try to predict what could happen but there are an enormous number of unexpected variants including particle size, wind speed and direction, turbulence, evaporation, sedimentation, and bacterial survival time .Survival time and what the organisms release into the soil are the two critical factors. If we make a mistake, one organism in 100,000 in the spray mix turns out to be a mutant but with unexpected and terrible results.
Studies are being carried out to see how well bacteria survive in agricultural sprays. In a greenhouse, some plants were sprayed with bacteria to simulate what might happen in a field. Damp air (high humidity) and low temperature made bacterial growth on the plants up to 65 times more likely after spraying. Bacteria also survive better if the spray contains larger droplets . Drifting downwind was noted but the strain being used tended not to establish itself unless concentrations on the plants were high .
Studies are also continuing to see how well genetically engineered bacteria survive in soil .If they get washed through by rainwater and if they will land up in streams and rivers or pollute reservoirs? Such studies are difficult and time consuming. But how well will such studies simulate the conditions in the outside world? The company Monsanto has developed a new strain of bacteria which is supposed to make the passage of the bacteria through soil more easily. This strain has been used first in a pre-release growth chamber and then in a limited field test. The tests were approved by the US Environmental Protection Agency . But it was tested only within the limited space.
But such bacteria bit later can release acids or other chemicals into the soil that make the soil unusable . Such organisms can be carried in dust on car wheels, on shoes, by strong winds, on the feet of animals or by insects. The effects could be devastating on an area, a country or a continent. This is perhaps one of the most worrying problems because finally it would be totally impossible to put the world right.
After all we can’t sterilise the entire planet. Further studies are realized to look at the survival of genetically changed bacteria in lakes. The experiments were done in special flow chambers where the water was constantly changing to simulate as closely as possible natural conditions after release. They found that the strains of altered bacteria they tested tended to survive as well as the original bacterias from which they were changed.
The survival could be greatly improved or lessened depending on how the organisms are modified. Even where there are strict regulations, unauthorised release of new organisms is already happening , sometimes this was carried out by those who consider the risks to be minimal.VIRUSES and HUMANITY. WHO WILL REMAINE ALIVE?Viruses are also a potential source of huge problems.
As we know there have already been suggestions that the AIDS epidemic caused by HIV could have been caused by a laboratory accident. So, we are faced with the fact that in the 1990’s we had the ability to create an enormous quantity of new viruses, many of which may have unpredictable results. Some of them will produce not so grave diseases and will be suitable as vaccines , others may turn out to be more lethal or more infectious. In the case of HIV variants, the only way to find out is on humans. Viruses can escape. The World Health Organization insists that the last surviving specimens of smallpox would be destroyed. The threat became a reality in 1982 in Birmingham University when a sample escaped from a damaged container and a laboratory worker became infected. She died and a major outbreak of smallpox was only prevented because there were enough people who had been vaccinated in the past.
And this was not the first such accident: in 1973 a smallpox outbreak at the London School of Hygiene and Tropical Medicine killed two people .Smallpox has now been completely erradicated worldwide by a global vaccination programme. Because of this the vaccinations have stopped If smallpox virus escape in an accident in ten or twenty years, most of the world’s population will be by then non-vaccinated people and a vast epidemic can result.Fortunately (according to the official data) all last remaining viruses have been destroyed. But perhaps they have not been. The temptation to keep such a powerful virus from extinction is great for those who wants to work on it genetically. Scientists are often untidy people: in 1985 the London School of Hygiene and Tropical Medicine was noticed in another smallpox scandal when traces of virus were found by accident in a fridge in the medical microbiology department – inside a biscuit tin where they had been since 1952.
There is also the possibility of industrial accidents as the number of factories growing genetically engineered organisms continues to increase. For bacteria, filamentous fungi, yeasts, mammalian cells and viruses the risks can be quite separate and different. For example, with bacteria, the main risk to factory or laboratory workers is infections of various kinds. For cell cultures the main risk is considered to be from dormant viruses. A recent report evaluating the range of risks came to the conclusion that they were small but also had to admit that such conclusions remained theoretical without concerning any occupational accidents or diseases attributed directly to genetically engineered organisms. The study concluded that only long term observations can confirm the low risk and consequently the highest measures of safety must still be used . Another sad case was an accidental infection of patients with viruses causing cancer as a result of injection with genetically engineered substances obtained from human cells growing in flasks. These cells are usually cancerous in origin.
If the situation doesn’t change viral material can be injected accidentally with increased risk of cancer in the future. Viral contamination of products continues to be an active concern . The fact that gives most cause for thinking is the invisible one of new strains of bacteria or viruses which find their way out of the gene factory and get into the soil, water supply or the bodies of animals or humans with disastrous results.
These new strains are now becoming available commercially and the control will become more and more difficult . The bacteria in our usual understanding is the bacteria which grow naturally in the human gut and which can be found elsewhere. But what if would creating by accident a new version of E. coli which turns out to release substances causing bowel cancer if they get into the human gut. It may be that this same gene has some other genetically engineered features such as producing a hormone to increase cow milk production.
E. coli organisms pass all the time between humans and they are rather important for our life. It is impossible therefore to control the spread of a strain of E. coli through a town or city. If it spreads in an unpredictable manner it can cause the resistance to antibiotics. Fortunately resistance is usually lost with time, unlike the resistance caused by a genetically engineered organism which could remain dangerous for a very long period and be hard to detect or control. Sometimes they talk about the contant use of GM materials.
The content use is the notion used to show that some measures are taken to limit contact between GMOs and the environment. The main dangerous point here that the GM is sometimes rather an unpredictable and there are no totally reliable tests for determining the results of the GM. For example, a very dangerous virus that kills all its victims was accidentally created by Australian scientists. It doesn’t make harm to the human organism but it closely referred to the substance that can be used in biowarfare.
The Australian scientists say the were no trying to create biowarfare or any dangerous virus, the purpose of the investigation was to make a mouse contraceptive vaccine for pest control . The former second-in-command of the civilian branch of the Soviet germ-warfare programme says it’s not so difficult to alter the virus they got into a dangerous virulent one. A gene that creates a big quantity of IL-4 was inserted into a mousepox virus.
IL-4(interleukin 4) is a molecule that appears in a natural way in the body. They were trying to make the animal infertile by stimulating antibodies against mouse eggs and the mouse virus was used only as a kind of vehicle to transport the egg proteins into mice. The result- appeared the virus which can be used as a dangerous biowarfare. With the IL-4 gene added this virus kills the animal in nine days. Ron Jackson from the Australian National University says about it(1999) : “ It would be safe to assume that if some idiot did put human IL-4 into human smallpox they’d increase the lethality quite dramatically”(n.p.
) (Rachel Nowak,1999). One of the scientists from Virginia, Alibek says(1999): ” I’d say any vaccine could be overcome by one or another genetically engineered virus or bacterium”(n.p.) (Rachel Nowak,1999).
Even more, the attempts to vaccinate the mice against the engineered virus hadn’t been successful. Anna Hill, a vaccine researcher from Oregon Health Sciences University in Portland says(1999)“ It’s surprising how very bad the virus is “(n.p.
) (Rachel Nowak,1999) So, the danger in producing GMOs viruses is obvious. GENETIC MODIFICATION – ONE MORE POINT IN FAVOUR OF TERRORISM. Germ warfare research has been carried on in secret for some considerable period of time. In the 1980’s the world was shocked by the assassination of two well known Bulgarian dissidents, one in Paris and the other in London. Both were killed in a similar way.
A special umbrella was used by someone following each of them. In each case a metal pellet was fired into the leg of the person. It felt like an insect bite. A few hours later when the wax coating on the pellet dissolved and an unknown biological weapon began to leak out. Within few hours each was in hospital dying.
The danger of germ weapons used on a large scale was raised by the Gulf War in early 1991 when it was revealed that Iraq possessed huge amounts of anthrax spores which could be spread over the desert using shells or helicopters, rendering large areas dangerous to humans. anthrax survives for a long period in normal conditions. In the 1940s a small Scottish Island was made totally uninhabitable for 50 years following experimental release of anthrax spores on the Island to see how effective they would be in germ warfare. Genetic engineers open horrifying possibilities to the producers of weapons . At the same time of course large amounts of vaccine are prepared to ensure that all the troops on your own side are fully protected. The best virus type would be one which can be passed to a large number of people easily either in a fine mist or in the water supply but which does not pass easily from person to person so the infection is contained in an area. A certain quantity of smallpox virus from a single helicopter in a single attack would be deadly to an unprotected army but would also create a disaster across a whole Germ warfare is extremely difficult to test , besides its rather hard to find volunteers for testing? Viruses are usually species specific so you cannot test new viral weapons on animals.
Viruses have unpredictable effects on large groups. For if someone is infected there is a chance of a mutation or adaptation. Viruses made by secret weapons research will of course be tested because without testing one has no weapon.
Where and on whom such tests will be carried out isn’t very clear. The certain thing is that it will not be on volunteers who know what is really being done. Who can predict what will be the results of the tests? Won’t one experiment cause an illness which can spread out of control? The answer to all these questions is that these things could happen and more than probably, we will see from time to time unexplained new diseases appearing suddenly in small groups before disappearing again. It’s very hard know the origin.
Germ warfare is an attractive terrorist option. After all it is hard to prove or disprove what they terrorist claims to be able to do. Because germ agents are unseen, a tiny amount of agent has the potential to terrorise and disrupt the lives of millions.
For example, if the terrorist telephones a national newspaper to say that a big quantity of nerve agents or hazardous viruses will be added to one of the thousands of distribution points of our domestic water supply. The most of population would be boiling all drinking water for weeks , especially if one or two had already died.MODIFICATING PEOPLE. May be it’s too early to speak about the global cloning of people though such attempts take already place, but today some measures are already taken that could have a very unwanted effects in future. Even today there are social consequences of genetic engineering. We already have techniques capable of providing couples with an 80% chance of having either a boy or girl .
Many fears have been expressed that with families becoming smaller such a situation will create great sex imbalances in future .People already know the catastrophic events that followed the China some years ago that only one child was permitted per family: very large numbers of baby girls were murdered at birth because a single child had to be a son. The second problem is now a long terms shortage of girls in some areas. This can cause grave social consequences in the future. The abstract. The main concern that has to take place in the case of Genetic Modification is obvious: the way of passing genes created artificially is more than dangerous. The nature transferring of genes is predictable, based on thousands years of evolution of our planet.
The problem is that the GM organisms also have the possibility to transfer their genes, the possibility even more strong and vivacious than nature-born’s one. And if the trial failed and didn’t give the positive results , it means that some unexpected and even horrible results must be awaited. Because falling into wild nature into the nature of legitimate birth chains, the modified gene can act itself in a very distinct and unpredictable manner. As we‘ve seen from the examples above, GM element can cause troubles in a very wide range of branches of human life. Genes used in a field to produce some new kinds of plants with more attractive characteristics are drawn by wind to another field and there extremely unwanted results could be expected. Animals created by transferring modified genes are perfect for production but if they fall into the natural eco-system they provoke big troubles for the rest of our planet’s fauna. GM foods can provoke grave illnesses in human’s body by treating in a wrong way the bacterias and cells living in our organism. Some viruses created to protect people turn to be horrible killing viruses as we saw in the case of E-coli bacteria, which provoked cancer.
The main fear is that the gene receiving the possibility to act out of human control can create new and new chains, relations and types of life, but will this new forms be safe for our life? The answer is obvious –they will not, because it’s impossible to create artificially an organism who would be identical to the natural organisms. Therefore, the connection of these two worlds(GM world and natural world) never will occur without problems and contradictions. Bibliography. 1) Cummins R. and Lilliston B..(2000). Genetically Engineered Food: A Self-Defense Guide for Consumers.
Marlowe ; Company. 2) Cummins R. (not mentioned). Hazards of Genetically Engineered Foods and Crops:Why We Need A Global Moratorium. Campaign for Food Safety/Organic Consumers Association. Retrieved April 1, 2005, from http://online.sfsu.edu/%7Erone/GEessays/gedanger.
htm 3) Gibbs W. Wayt (2004). Synthetic Life: Biologists are crafting libraries of interchangeable DNA parts and assembling them inside microbes to create programmable, living machines. Scientific American April 26.
Retrieved 2 April, 2005, from http://online.sfsu.edu/%7Erone/GEessays/gedanger.
htm 4) Leary Warren E. (1996). Genetic Engineering of Food Can Spread Serious Allergies. New York Times, March 14. Retrieved April 2, 2005, from http://online.
sfsu.edu/%7Erone/GEessays/gedanger.htm 5) Mae-Wan Ho.(1998). Genetic Engineering, Dream or Nightmare. Gateway Books.. 6) Marilyn Berlin Snell.
(1995). Bioprospecting or Biopiracy? The hunt for genetic riches in the developing world . Retrieved April 1, 2005, from http://online.sfsu.edu/%7Erone/GEessays/gedanger.
htm 7) Pollak A. (2001). With Biotechnology, a Potential to Harm.
New York TimesNovember 27. Retrieved April 2 , 2005 from http://online.sfsu.
edu/%7Erone/GEessays/gedanger.htm 8) Preston R. (1999). The demon in the freezer. Hardcopy The New Yorker, July 12, 1999, pp. 44-61.
Retrieved April 2, 2005, from http://online.sfsu.edu/%7Erone/GEessays/gedanger.htm 9) Pusztai A., (2001). Genetically Modified Foods: Are They a Risk to Human/Animal Health? Retrieved April 1, 2005, from http://www.actionbioscience.org/biotech/pusztai.
html 10) Rachel Nowak, Melbourne (1999). Killer virus: An engineered mouse virus leaves us one step away from the ultimate bioweapon. Retrieved April 1, 2005 from, http://online.sfsu.edu/%7Erone/GEessays/gedanger.htm 11) Shiva Vanadana (not mentioned). Bioterror And Biosafety Retrieved April 2, 2005, fromhttp://online.sfsu.
edu/%7Erone/GEessays/gedanger.htm 12) Steinbrecher R., (1998). What is Genetic Engineering? A Magazine of Green Social Thought, Vol.
18 (Winter 1999), pp. 9-12. Retrieved April 1, 2005 from, http://online.sfsu.
edu/%7Erone/GEessays/gedanger.htm 13) Ticciati R. and Ticciati L (1998). Genetically Engineered Foods: Are They Safe? You Decide. Keats. 14) Watson R.
(2001). Secret US germ tests threat to treaty. The Times (London)Wednesday, September 05.
Retrieved 1 April, 2005, from http://online.sfsu.edu/%7Erone/GEessays/gedanger.htm 15) Without the author, (1999). GM trees threaten the global environment.
Retrieved April 2, 2005 , from http://online.sfsu.edu/%7Erone/GEessays/gedanger.htm;
