Tsetse flyTsetse (ˈsiːtsi , ˈtsiːtsi or ˈtsɛtsə ) (sometimes spelled tzetze; also known as tik-tik flies) are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus Glossina, which are placed in their own family, Glossinidae. The tsetse is an obligate parasite, which lives by feeding on the blood of vertebrate animals. Tsetse has been extensively studied, because of their role in transmitting disease.
G-type main-sequence starA G-type main-sequence star (spectral type: G-V), also often, and imprecisely called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K. Like other main-sequence stars, a G-type main-sequence star converts the element hydrogen to helium in its core by means of nuclear fusion, but can also fuse helium when hydrogen runs out.
A-type main-sequence starAn A-type main-sequence star (A) or A dwarf star is a main-sequence (hydrogen burning) star of spectral type A and luminosity class (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1.4 and 2.1 solar masses () and have surface temperatures between 7,600 and 10,000 K. Bright and nearby examples are Altair (A7), Sirius A (A1), and Vega (A0). A-type stars do not have convective zones and thus are not expected to harbor magnetic dynamos.
B-type main-sequence starA B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars are extremely luminous and blue. Their spectra have strong neutral helium absorption lines, which are most prominent at the B2 subclass, and moderately strong hydrogen lines. Examples include Regulus and Algol A.
F-type main-sequence starAn F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables VII and VIII. This temperature range gives the F-type stars a whitish hue when observed by the atmosphere. Because a main-sequence star is referred to as a dwarf star, this class of star may also be termed a yellow-white dwarf (not to be confused with white dwarfs, remnant stars that are a possible final stage of stellar evolution).
K-type main-sequence starA K-type main-sequence star, also referred to as a K-type dwarf red dwarf, or orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ("red dwarfs") and yellow/white G-type main-sequence stars. They have masses between 0.6 and 0.9 times the mass of the Sun and surface temperatures between 3,900 and 5,300 K. These stars are of particular interest in the search for extraterrestrial life due to their stability and long lifespan.
Main sequenceIn astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium.
Sterile insect techniqueThe sterile insect technique (SIT) is a method of biological insect control, whereby overwhelming numbers of sterile insects are released into the wild. The released insects are preferably male, as this is more cost-effective and the females may in some situations cause damage by laying eggs in the crop, or, in the case of mosquitoes, taking blood from humans. The sterile males compete with fertile males to mate with the females. Females that mate with a sterile male produce no offspring, thus reducing the next generation's population.
O-type main-sequence starAn O-type main-sequence star (O V) is a main-sequence (core hydrogen-burning) star of spectral type O and luminosity class V. These stars have between 15 and 90 times the mass of the Sun and surface temperatures between 30,000 and 50,000 K. They are between 40,000 and 1,000,000 times as luminous as the Sun. The "anchor" standards which define the MK classification grid for O-type main-sequence stars, i.e. those standards which have not changed since the early 20th century, are (O7 V) and (O9 V).
TrypanosomiasisTrypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. In humans this includes African trypanosomiasis and Chagas disease. A number of other diseases occur in other animals. African trypanosomiasis, which is caused by either Trypanosoma brucei gambiense or Trypanosoma brucei rhodesiense, threatens some 65 million people in sub-Saharan Africa, especially in rural areas and populations disrupted by war or poverty.
