I can't understand sense of this text !!! help please !!!explain about what the speech in this text Students who stay up all night to cram for an exam are doing themselves more harm than good, according to research into the link between sleep and memory published yesterday. Scientists at Harvard Medical School discovered that people who deprive themselves of sleep so that they can study until the last minute are unlikely to remember anything that would improve their performance, while suffering the crippling effects of fatigue. The scientists found that the brain needs good-quality sleep immediately after practising a task if it is to learn to improve at it. Those who substitute study for sleep particularly those who miss deep or “slow-wave” sleep will get little benefit from their extra effort. Instead, they may perform worse than expected because tiredness is a major cause of poor decision-making.