Man-made effects

Cyclical changes over shorter time scales are harder to spot in the records because they are usually much weaker than seasonal oscillations and can be masked by random variations in the data. Daily cycles have not been observed but possible ambient error sources at Mauna Loa include volcanic, vegetative and man-made effects (e. g. vehicular traffic and industry). Daily peaks in measured concentrations occur because of complex wind currents. Downslope winds often transport CO2 from distant volcanic vents, causing elevations in measured CO2 concentrations. Upslope winds during afternoon hours are often low in CO2 because of photosyn-... 

The telecommunication plant is made of a number of metal and non-metal components, exposed to various corrosive environments. Man-made effects, such as DC stray currents, can further accelerate corrosion of the plant. 

Within the constraints of this article it is impossible to be comprehensive in the coverage of the subject matter, in terms of the chemicals involved and in the widely varying practices and areas of the world in which the title compounds are ingested by farmed animals. This account is, however, intended to give an overview, citing some relevant examples, of the beneficial and adverse effects, in animals and on the environment, of man-made compounds and naturally produced compounds in extensive and commercial production systems. 

The rotation of plane polarized hght (either -I- or -) is not a man-made convention. It is a physical effect that is measured in the lab. It is impossible to predict whether a compound will be -l- or - without actually going into the lab and trying. If a stereocenter is R, this does not mean that the compound will be +. It could just as easily be. In fact, whether a compound is -l- or - will depend on temperature. So a compound can be + at one temperature and - at another temperature. But clearly, temperature has nothing to do with R and S. So, don t confuse R/S with +/-. They are totally independent and unrelated concepts. 

For the most part, plastics are man-made since very few plcistlcs are natural, i.e.- nature-made. Natural plastics include large molecular-wei t proteins and similar molecules. Man-made plastics can be classified as either thermoplastic or thermosetting. Each class derives its physical properties from the effects of application of heat, the former becoming "plastic" (that is- it becomes soft and tends to flow) while the latter becomes less "plastic" and tends to remain in a softened state. This difference in change of state derives from the actual nature of the chemical bonds in the polymer. Thermoplastic polymers generally consist of molecules composed of many monomeric units. A good example is that of polyethylene where the monomeric unit is -(CH2-CH2)-. The molecule is linear... 

The most dangerous in their long-term effects are the tailing dumps containing radio-active waste, which are also located in the vicinity of the Dnepr bed or near smaller rivers in the Dnepr catchment basin. Many tailing dump levees and toxic radio-active waste hoarder dams are in extremely poor condition. They can be easily destroyed by natural factors (minor earthquakes, floods, rise of subterranean waters) or by man-made acts (like a terrorist act with the use of explosives), with all ensuing consequences. 

Furthermore, following concerns over the way the ozone layer is being damaged by man-made chemicals, some UV-c now reaches the Earth s surface, particularly in Australasia and some parts of South America. People living in such places are not adequately protected against the harmful effects of the sun s rays by the melanin in their skin. 

The data reviewed in Chapter 4 support the second point of view. Measurements in remote areas of the Northern Hemisphere, when compared with those in the lower 48 states of the United States, support the contention that man-made sources are involved in cases where the standard is exceeded. Further measurements are needed to establish this contention with more certainty. Some of the difficulties involved in such studies become apparent when it is noted that the effect of pollution— particularly nitric oxide emission—is to reduce ozone concentrations locally. 

England - Department of Health - Committee on Medical Aspects of Radiation in the Environment (COMPARE). Online. Available HTTP comare/comare.htm> (accessed 9 April 2003). COMPARE is responsible for assessing and advising agencies on the health effects of natural and man-made radiation in the environment . 

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