This tactile feedback is related to a difference in tis-sue density as one goes from the parenchyma to the vessels or from the parenchyma to the collecting sys-tem, and also to the selectivity of the CUSA to spare tissue of high collagen content.
1 In the least developed countries, the overall illiteracy rate is 49 percent. 2  52 percent of all non-literates live in India and China. 3  Africa as a continent has a literacy rate of less than 60 percent. 4  In Sub-Saharan Africa since 1980, primary school enrollment has declined, going from 58 percent to 50 percent.
Africa's population is the youngest amongst all the continents; 50% of Africans were born in 1991 or later Algeria is Africa's largest country by area, and Nigeria by population.n some African states, half or more of the population is under 25 years of age. The total number of people in Africa increased from 229 million in 1950 to 630 million in 1990. As of 2014, the population of Africa is estimated at 1.2 billion.