2. 外语
  3. Electronic Radiation Puts Your Health at Risk Electric power systems work at around 50 Hz just above the naturally occurring

Electronic Radiation Puts Your Health at Risk Electric power systems work at around 50 Hz just above the naturally occurring

admin2010-05-09  41
问题                                     Electronic Radiation Puts Your Health at Risk
    Electric power systems work at around 50 Hz just above the naturally occurring frequency of 30 Hz generated by the Earth. Our bodies are tuned in to this low frequency so any frequency close to this is going to interfere with us, such as the 50 Hz AC mains power system used in the UK. ELF (Extremely Low Frequency) electromagnetic fields vibrating from 0.5 to 100 Hz, even if they are weaker than the Earth’s field, interfere with the cues that keep our biological cycles properly timed.
    The frequencies that ELF AC systems use are very close to the natural brain rhythms of man. The pineal gland (松果体) is the principal structure in the brain that is directly sensitive to the earth’s magnetic field. As a result it functions abnormally when exposed to abnormal fields close to its own. Because the pineal gland produces a host of psychoactive chemicals, its abnormal functioning can cause neurological and behavioral problems.
Studies and Reports
    The biological and medical data currently available showing the danger of ELF AC mains power frequency magnetic fields is as conclusive as the data relating to cigarette smoking and lung cancer.
    The European Parliament has passed a motion for a resolution on combating the harmful effects of electromagnetic fields. Since September 1992 Sweden has officially acted on the basis that there is a connection between exposure to power frequency magnetic fields and the incidence of cancer, childhood cancer in particular.
    In 1990 the United States Environmental Protection Agency stated "In conclusion, after an examination of the available data over the past 15 years, there is evidence of a positive association of exposure to magnetic fields with certain site-specific cancer, namely leukaemia, cancer of the central nervous system, and to a lesser extent, lymphomas (淋巴瘤). This is supported by many studies of children and adults across many different populations and subgroups."
What Can the Biological Effects Be?
    An electromagnetic field affects growing cells, and acts as a cancer promoter. Cancer cells can increase their rate of growth significantly and develop more malignant characteristics. It also affects learning ability and behavioral and psychological mechanisms increasing the incidence of depression and suicide. Chronic exposure may lead to an increase in the incidence of brain tumors. Your brain’s EEG (脑电图) rhythms change when a light switch is operated nearby. A stress response occurs which, if prolonged, can lead to an immune-system deficiency, resulting in an increased incidence of infectious diseases and cancers. Because of the effects on growing cells, young children and babies are especially at risk. Studies have shown that risks of children’s cancer could increase.
What Are the Risks?
    Electricity is part of our daily life. We are constantly using electrical appliances at home and at work, such as computers, photocopiers, clock radio alarms, electric blankets, microwave ovens—all with the necessary AC mains transformers and wiring. All of these produce ELF electromagnetic fields. The more power the appliance consumes the stronger the field it creates.
    If you spend long periods of time close to a wiring circuit or appliance with a strong field such as a computer screen, television screen, heater, clock radio or electric blanket, you may be at risk. You may also be at risk if you live close to high voltage power lines (above or below ground) and their distribution transformers. The probable safe level for constant exposure now being discussed is 1 milligause (less for children). It would seem appropriate to exercise "prudent avoidance" and limit the exposure to you, your family and work colleagues wherever possible.
The Appliances That Make Your Brain Blow a Fuse
    Brain performance can be impaired by as little as five minutes exposure to common domestic electronic appliances, researchers claim. Objects such as computers, televisions and mobile phones can cause a lack of concentration, headaches, anxiety and even insomnia and depression, a study has shown.
    The findings reopen the debate over the effects of electromagnetic radiation, which is emitted by all electrical appliances.
    Tests were carried out in America on a new device, which claims to help the body counter electromagnetic fields, Volunteers had a digital clock held six inches from their head for five minutes during which time scientists noted "anomalous brainwave activity" which, after a prolonged period, can lead to so-called electromagnetic depression.
    Symptoms of this condition include mild depression, anxiety, mood swings and low energy. The researchers, led by Professor William Tiller and Neurosurgeon Professor Norman Shealy, found the effects were lessened when volunteers wore the new pendant-shaped device for one month. Called a QLink and selling for ￡89, it contains special cells which are said to replicate the natural electromagnetic forces of the human body and harmonize them with man made ones.
How to Measure Magnetic Field Strength?
    A Gauss is a common unit of measurement of magnetic field strength. A Gauss meter is an instrument which measures the strength of magnetic fields. Gauss meters may vary in the strength of the magnetic field they are capable of measuring. A meter used for measuring EMFs from power lines, transformers, substations and appliances around the home, for example, should be able to measure as low as.1 mg.
    The digital clock experiment emitted a field of six milligauss, but emission from many electrical appliances positioned at a similar distance from the head produce considerable greater counts. A computer screen emits 20 milligauss and a mobile phone up to 100.
Prudent Avoidance
    Electricity is an inseparable part of our modern day society. This means that EMFs will continue to be all around us. But as Discovery Magazine postulated, aside from making our life easier, is electricity also making our lives shorter?
    Most experts agree that limited, non-chronic exposure to EMFs is not a threat. For example, it is probably acceptable for a person to be near a toaster in the morning. However, it is not advisable for a person to sleep under ail electric blanket, live near a powerline/substation, and sleep in a room where the power enters the home. This person is under an extreme case of chronic exposure. This condition, unfortunately, applies to millions of Americans.
    If you wish to follow the EPA’s advice and practice "prudent avoidance", then the following advice is offered:
    Measure your home, work and school environments with a Gauss meter. Measure EMFs both inside and outside your home. Don’t let your children play near power lines, transformers, radar domes.
    Avoid areas where the field is above 1 mg. Measure the EMFs from appliances both when they are operating and when they are turned off. Some appliances (like TVs) are still drawing current even when they are off.
    Don’t sleep under an electric blanket or on a waterbed. If you insist on using these, unplug them before going to bed (don’t just mm it off). Even though there is no magnetic field when they are turned off, there may still be a high electric field.
    Rearrange your office and home area so that you are not exposed to EMFs from the sides/backs of electric appliances and computers. In the home, it is best that all major electrical appliances, such as computers, TVs, refrigerators etc, be placed up against outside wails. That way you are not creating an EMF field in the adjoining room.
    Don’t sit too close to your computer. Computer monitors vary greatly in the strength of their EMFs, so you should check yours with a meter. Don’t stand close to your microwave oven. Move all electrical appliances at least 6 feet from your bed. Eliminate wires running under your bed.
    And last but not least, always always always remember that EMFs pass right through walls. The EMF you are reading on your Gauss meter could be radiating from the next room or from outside your home.
If the power frequency is weaker than the frequency generated by the Earth, it will not have any influence on us.
选项 A、Y
B、N
C、NG
答案B
解析 参看第一段最后一句话“ELF (Extremely Low Frequency) eletromagnic fields vibrating from 0.5 to 100Hz，even if they are weaker than the Earth’s field，interfere with the cues that keep our biological cycles properly timed”．
转载请注明原文地址:https://kaotiyun.com/show/QbKK777K
0

大学英语六级

相关试题推荐
随机试题
最新回复(0)