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Displaying 135 of about 301 resultsRadio blackout is a prolonged period of fading or faded radio communications, primarily in the high frequency range from ionospheric changes because of increased solar activity, in particular solar flares of C-class level or higher on the sunlit side of Earth (AMS, 2018).
An ionospheric storm is defined as turbulence in the F region of the ionosphere, usually due to a sudden burst of radiation from the Sun (WMO, 1992).NB. The F region is the highest region of the ionosphere, at altitudes greater than 160 km (100 miles).
A meteorite is an object that survives a trip through Earth’s atmosphere and hits the ground (adapted from NASA, no date).
Deforestation is the conversion of forest to other land use independently of whether human-induced or not (FAO, 2020).
Soil erosion is defined as the accelerated removal of topsoil from the land surface through water, wind and tillage (FAO, 2020).
Nonpoint sources of pollution refer to pollution sources that are diffused and without a single point of origin or not introduced into a receiving freshwater or maritime environment from a specific outlet. The pollutants are generally carried off the land by storm-water run-off. The commonly used categories for nonpoint sources are agriculture, forestry…
Fluoride is a naturally occurring mineral to which the public are often exposed via drinking-water. Depending on dose intake fluoride may have both beneficial effects (reducing the incidence of dental caries) or negative effects (causing tooth enamel and skeletal fluorosis following prolonged high exposure) (adapted from NCBI, 2020 and WHO, no date).
Benzene is a clear, colourless, highly flammable and volatile, liquid aromatic hydrocarbon (molecular formula C6H6) with a gasoline-like odour (WHO, 2019).
Hazardous pesticide contamination in soils often results from improper storage of (obsolete) agrochemicals, as a result of which pesticides are spilled in the surroundings of the storage site, where they seep into the soil or are dispersed by wind. In some cases, pesticide spillage has been ongoing for many years. Such spillage may cause serious soil or…
Insecticides are chemicals used to control insects by killing them (CDC, 2019).
There are a number of causal agents recognised for oyster diseases. Examples of major oyster diseases and their causal protozoan agents are: bonamiosis (Bonamia exitiosa, B. ostreae); marteiliosis (Marteilia refringens); perkinsosis (Perkinsus marinus, P. olseni). These oyster diseases are notifiable OIE-listed diseases and occur worldwide (OIE, 2019).
Trypanosomiasis, human African (sleeping sickness) is caused by protozoan parasites belonging to the genus Trypanosoma transmitted by infected tsetse flies and is endemic in 36 sub-Saharan African countries. Without treatment, the disease is considered fatal, where there are tsetse flies that transmit the disease (WHO, 2020).
Rift Valley fever (RVF) is an acute haemorrhagic viral disease, affecting small and large ruminants and camels. RVF virus is a member of the Phlebovirus genus. The disease causes high mortality especially in new borne and mass abortions in pregnant animals. Humans become infected from contact with tissues/blood of infected animals including abortive mat…
Foot-and-mouth disease is caused by a virus of the family Picornaviridae, genus Aphthovirus. It is a highly contagious and economically important disease of cloven-hoofed domestic animals (cattle, buffaloes, pigs, sheep, goats) and wild animals (FAO, 2012; OIE, 2018).
Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus called SARS-associated coronavirus (SARSCoV) (WHO, 2019).