The brain-drain:  a sub-system of centre-periphery relationship.
Mandi
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D000569:Americas; D002170:Canada; D003710:Demography; D019049:Developed Countries; D003906:Developing Countries; D004641:Emigration and Immigration; D005060:Europe; D009656:North America; D009790:Occupations; D011153:Population; D011157:Population Dynamics; D011640:Public Policy; D012111:Residence Characteristics; D006113:United Kingdom; D014481:United States
Americas; Brain Drain; Canada; Demographic Factors; Developed Countries; Developing Countries; Europe; International Migration; Migration; Migration Policy; North America; Northern America; Northern Europe; Occupations; Place Of Birth; Population; Population Dynamics; United Kingdom; United States