IELTSwithJurabek

Read the text and answer questions 14-26

Sleep – who needs it?

It appears that some animals can survive on remarkably little sleep. Could this also be the case for humans?

A As any new parent knows, the first months of an infant's life mean little sleep for the family. But humans have it easy compared to orcas, also known as killer whales. University of California, Los Angeles, neuroscientist Jerome Siegel and post-doctorate fellow Oleg Lyamin have found that for the first month after giving birth, killers whale mothers and their calves do not experience normal sleep at all, and neither stops moving for more than a few minutes at a time. The young orcas’ movement and wakefulness help them keep their body temperature constant until mass and blubber insulation develop and allow for frequent respiration. Meanwhile the mothers of newborn orcas must constantly look out for sharks, while teaching the calves to breath.

B According to Siegel, the results of his orca study fundamentally change our view of sleep. ‘It has often been said that sleep is necessary for an animal’s primary development, particularly that of the brain,’ Siegel says. ‘But here we have a creature which grows one of the largest brains in the animal kingdom, and yet it is doing this without sleep.’ All mammals and birds appear to need sleep, but scientists are unsure if reptiles and fish do. ‘When you come downstairs at three in the morning, the goldfish isn’t lying on the bottom of the bowl, it’s swimming around,’ Siegel says. But other scientists believe fish do enter a restful dormant state that is at least similar to sleep.

C Some animals die without proper sleep, and experiments have shown that sleep deprivation can cause death more quickly than food deprivation. Two weeks without sleep can kill laboratory rats. Sleep is clearly important, but what determine how much we sleep, and when? Siegel thinks that the sleep an animal needs is dictated less by biological functions than by the animal’s environmental niche. Availability of food is a major factor. The long rest typical of bats, for example, helps the animas to economize on energy. ‘If a bat eats insects for only three hours in the evening, then maybe the best thing is to go hang in a cave upside down for the rest of the day,’ Siegel says.

D Sleep is not the same for all creatures. In dolphin’s half the brain may rest while the other half stays vigilantly awake, and the animal carries on everyday activities. Dolphins sleep literally with one eye closed — the eye on the opposite side of the body to the dozing brain hemisphere, since the right brain hemisphere works the left eye and vice versa. However, for unknown reasons, closed eyes seem to be a virtually universal prerequisite for sleep.

E Neuroscientist Clifford Saper of the Harvard Medical School has located a small area at the base of the brain called the ventrolateral preoptic nucleus that sends chemical signals to other parts of the brain during sleep to slow those brain parts down and determines the best sleep budget for the animal. It is flexible, able to reverse the normal nocturnal habits of a rodent to make it sleep at night, if day is the only time the rodent can find what it needs to eat. According to Saper, evidence suggest that for restoring tried muscles or any other body system, sleep is no more effective than a comparable period of wakeful resting – except for one critical organ, the brain. The human brain apparently cannot do without sleep. Studies show that prolonged wakefulness leads to degradation of memory, alertness, coordination and judgment.

F Nevertheless, studies of species exhibiting ‘natural models of sleep deprivation,’ as psychologist Verner Bingman of Ohio’s Bowling Green State University calls them, may allow researchers to provide us with new methods for adapting to limited sleep without losing effectiveness. 'We could live 20-hour lives instead of 12-or-14-hour lives,' says Bingman, who is studying the behavior of the migratory birds Swainson’s thrushes, which for migration purposes, go from a normal night’s sleep of 10 to 12 hours down to about 2.5 hours so they can fly at night. To handle the energy output of the long journey they must nearly double the amount of fat in their bodies. They have to switch from a diet of seeds to one of fruits and insects, which they must search for during the day, so further limiting their sleep time.

G Bingman and doctoral student Thomas Fuchs have discovered that during morningand midday hours the thrushes enter phases of drowsiness, during which they take as many as 50 micro naps per hours, most of them lasting about 10 to 20 seconds. 'When brain waves are measured, these napping behaviors look very much like normal sleep,' says Bingman. 'The trick would be to develop techniques or drugs that could recreate a similar brain pattern in humans.' Saper, however, disagree. ‘The effect of 20 hours of wakefulness on driving is the equivalent of two shots of whiskey,’ he warns. ‘Sleep deprivation is unfortunately a major cause of death in the US in young adults, who have a very high crash rate between 3 and 6 am.’ He thinks we are dreaming if we think we’re ever going to get by on as little sleep as newborn orcas or migrating thrushes

Read the text and answer questions 27-40

Looking at daily life in ancient Rome

In this preface to a history the writer explains the factors affecting the scope of his study

If our ideas on Roman life are not to become lost in confusion, we must study it within as strictly defined time. Nothing changes more rapidly than human customs. Looking at our own more familiar world, apart from the great scientific discoveries of recent centuries which have turned it upside down – steam, electricity, railways, motor cars and aeroplanes, for example it is clear that the elementary forms of everyday life have been subject to increasing change. Potatoes. for example, were not introduced into Europe until the sixteenth century, coffee was first drunk there in the late sixteenth or early seventeenth, and the banana was used in desserts in Europe at the beginning of the twentieth. The law of change was not less operative in antiquity. It was a commonplace of Roman rhetoric to contrast the crude simplicity of the Republic (509-27BC) with the luxury and refinement of the imperial times which followed. There is no common measure whether of home or house or furniture. Between ages which are so different.

Since a choice of time must necessarily be made, this history will confine itself to studying the generation which was born about the middle of the first century AD, toward the end of the reign of Claudius (41-54 AD) or the beginning of the reign of Nero (54-68 AD), and which lived on into the reign of Trajan (98-117 AD) and of Hadrian (117-138 AD). This generation saw the Roman Empire at its most powerful and prosperous. It was witness to the last conquests of the Caesars: the conquest of Dacia, in modern-day eastern Europe, which brought vast mineral wealth into the Empire, and the conquest of Arabia, which helped to bring the riches of India and East Asia flooding into Rome. In the material domain, this generation attained the pinnacle of ancient civilization.

By a fortunate coincidence – all the more fortunate in that Latin literature was soon to run nearly dry – this generation is the one whose records combine to offer us the most complete picture of Roman life that we possess. We have a profusion of vivid and picturesque descriptions, precise and colourful, in such works as the Epigrams of Martial, the Satires of Juvenal and the Letters of Pliny. In addition, the Forum of Trajan in Rome itself and the ruins of Herculaneum and Pompeii, the two prosperous resorts buried by eruption of Mount Vesuvius in 79AD, supply an immense fund of archaeological evidence. Later excavations have also restored to us the ruins of the city of Ostia, which date in the main from the time when the Emperor Hadrian created this great commercial city as a realisation of his town planning ideas. Fortune has favoured the historian of this time.

It is not enough to focus our study of Roman life only on a fixed time. It would lack foundation and consistency if we did not also focus it in space – in the country or in the town. Even today when the facilities for communication bring something of the city into the smallest and most isolated country cottage, there remains a significant difference between rural existence and the excitement of city life: a much greater gulf separated the peasant from the townsman of antiquity. So large was the inequality between them that, according to the historian Rostovtzeff, it pitted one against the other in a fierce and silent struggle which pierced the wall protecting the Roman privileged classes from the barbarian flood from the north. When the barbarian forces began to invade Roman territory, the peasants decided to fight alongside them.

The townsman, in fact, enjoyed all the goods and resources of the earth. The peasant knew nothing but unending labour without profit and was unable to enjoy the activities available in even the poorest of cities: the liveliness of the sports field, the warmth of the public baths and the magnificence of public spectacles. In a work on the history of everyday life, we must give up any attempt to blend two such dissimilar pictures into one and must choose between them. The time which we have chosen to describe day by day is that of those Roman subjects who spent their time exclusively in the town, or rather in the ity, Rome, which they regarded as the hub and centre of the universe, proud and wealthy ruler of a world which seemed at that time to have been pacified forever.

To perform our task well, we must first try to form an adequate picture of the surroundings in which our subjects lived, and by which their lives were coloured, freeing ourselves from any misconceptions concerning it. We must seek to reconstruct the physical nature of the great city and the social milieu of the various classes of the hierarchy by which it was governed. We must also investigate the moral background of thought and sentiment which can help explain both its strength and its weaknesses. The way in which the Romans of Rome employed their time can only be studied satisfactorily after we have plotted out the main lines of the framework within which they lived and outside of which the routine of their daily life would be more or less unintelligible.