Spectral analysis of fetal sheep EEG during hypoxia.
Abstract Power spectra and coherence functions were obtained on samples of EEG recorded from fetal sheep in utero . Hypoxia was produced by respiring the ewe on gas mixtures containing reduced oxygen pressure. With both halothane and local anesthesia, the EEG changes associated with hypoxia consisted of an early power reduction in higher frequencies followed by a reduction of over-all amplitude leading to the isoelectric stage. The times at which statistically significant changes occurred were not earlier during the progressive fall of fetal arterial pO 2 than visual estiamtes of abnormality made on line from the paper record and were in all cases later than significant cardiovascular changes.
Development of sleep and wakefulness in the foetal lamb.
Abstract The evolution of cortical activity was studied from 0.6 of term in utero in eleven foetal lambs, and through most of parturition and the early post-partum period in two newborn lambs. At 0.8 of term the alternating periods of wakefulness and sleep were definite. During a period of electrocorticographic desynchronization paradoxical sleep could be recognized by the return to slow wave sleep that occurs at the sounding of a bell and also by rapid eye movements. No apparent major modification of electrocortical activity accompanied the transition from intra-uterine to extra-uterine life. At parturition there was a sudden increase in muscular tone and a 50% decrease in paradoxical sleep.
THE ATLANTIC SLAVE TRADE AND COLONIALISM: REASONS FOR AFRICA’S UNDERDEVELOPMENT?
It is probably an understatement to assert that Africa, the world’s second largest continent, is underdeveloped compared with other continents. Two major exogenous factors often cited for Africa’s development crisis are the so called ‘dual historical injustices’ – the Atlantic slave trade and colonialism. It is often pointed out that while the former almost completely arrested and retarded Africa’s demographical growth for more than three centuries, evoked a perennial state of acrimony and warfare and created a tense and unprecedented atmosphere of insecurity which hindered economic activities and stifled local entrepreneurship and technological drive and dislocated Africa’s socio-economic and political structures and institutions; the latter tied African countries to the apron strings of western imperial powers thereby rendering the pre-conditions necessary for socio-economic and political transformation unachievable. This paper contends that while the history of Africa’s underdevelopment may be traceable to the Atlantic slave trade and colonialism, African leaders had made enormous contributions to the continent’s underdevelopment and backwardness. The paper concludes that irresponsible and irresponsive leadership, vampirism and prodigality, corruption, lack of respect for democratic ideals, insecurity, endemic civil wars, nepotism, etc are the fundamental causes of Africa’s underdevelopment.