Cambridge 10

C10 T1 P1 Stepwells

A millennium ago, stepwells were fundamental to life in the driest parts of India. Although many have been neglected, recent restoration has returned them to their former glory. Richard Cox travelled to north-western India to document these spectacular monuments from a bygone era.

Một thiên niên kỷ trước, giếng bậc thang là nền tảng cho cuộc sống ở những vùng khô hạn nhất của Ấn Độ. Mặc dù nhiều người đã bị bỏ quên, nhưng việc phục hồi gần đây đã đưa chúng trở lại vinh quang trước đây. Richard Cox đã đi đến phía tây bắc Ấn Độ để ghi lại những di tích ngoạn mục này từ một thời đại đã qua.

During the sixth and seventh centuries, the inhabitants of the modern-day states of Gujarat and Rajasthan in North-western India developed a method of gaining access to clean, fresh groundwater during the dry season for drinking, bathing, watering animals and irrigation. However, the significance of this invention – the stepwell – goes beyond its utilitarian application.

Trong thế kỷ thứ sáu và thứ bảy, cư dân của các bang Gujarat và Rajasthan ngày nay ở Tây Bắc Ấn Độ đã phát triển một phương pháp tiếp cận với nước ngầm sạch, trong lành trong mùa khô để uống, tắm, tưới nước cho động vật và tưới tiêu. Tuy nhiên, tầm quan trọng của phát minh này - giếng bậc thang - vượt ra ngoài ứng dụng thực dụng của nó.

Unique to the region, stepwells are often architecturally complex and vary widely in size and shape. During their heyday, they were places of gathering, of leisure, of relaxation and of worship for villagers of all but the lowest castes. Most stepwells are found dotted around the desert areas of Gujarat (where they are called vav) and Rajasthan (where they are known as baori), while a few also survive in Delhi. Some were located in or near villages as public spaces for the community; others were positioned beside roads as resting places for travellers.

Độc đáo trong khu vực, các giếng bậc thang thường có kiến trúc phức tạp và rất khác nhau về kích thước và hình dạng. Trong thời kỳ hoàng kim của họ, chúng là nơi tụ tập, giải trí, thư giãn và thờ cúng cho dân làng thuộc tất cả các đẳng cấp thấp nhất. Hầu hết các giếng bậc thang được tìm thấy rải rác xung quanh các khu vực sa mạc của Gujarat (nơi chúng được gọi là vav) và Rajasthan (nơi chúng được gọi là baori), trong khi một số ít cũng tồn tại ở Delhi. Một số được đặt trong hoặc gần các ngôi làng làm không gian công cộng cho cộng đồng; một số khác được đặt bên đường làm nơi nghỉ ngơi cho khách du lịch.

As their name suggests, stepwells comprise a series of stone steps descending from ground level to the water source (normally an underground aquifer) as it recedes following the rains. When the water level was high, the user needed only to descend a few steps to reach it; when it was low, several levels would have to be negotiated.

Đúng như tên gọi, giếng bậc thang bao gồm một loạt các bậc đá dẫn xuống từ mặt đất đến nguồn nước (thường là tầng chứa nước ngầm) khi mực nước rút xuống sau những trận mưa. Khi mực nước cao, người dùng chỉ cần xuống vài bậc thang là đến được nguồn nước; khi mực nước thấp, họ phải vượt qua nhiều bậc thang khác nhau.

Some wells are vast, open craters with hundreds of steps paving each sloping side, often in tiers. Others are more elaborate, with long stepped passages leading to the water via several storeys. Built from stone and supported by pillars, they also included pavilions that sheltered visitors from the relentless heat. But perhaps the most impressive features are the intricate decorative sculptures that embellish many stepwells, showing activities from fighting and dancing to everyday acts such as women combing their hair and churning butter.

Một số giếng là những miệng núi lửa rộng lớn, mở với hàng trăm bậc thang lát mỗi bên dốc, thường là theo từng tầng. Những cái khác phức tạp hơn, với những lối đi dài bậc thang dẫn đến mặt nước qua nhiều tầng. Được xây dựng bằng đá và được hỗ trợ bởi các cột trụ, chúng cũng bao gồm các gian hàng che chở du khách khỏi cái nóng không ngừng. Nhưng có lẽ đặc điểm ấn tượng nhất là các tác phẩm điêu khắc trang trí phức tạp tô điểm cho nhiều giếng bậc thang, thể hiện các hoạt động từ chiến đấu và khiêu vũ đến các hành động hàng ngày như phụ nữ chải tóc và khuấy bơ.

Down the centuries, thousands of wells were constructed throughout northwestern India, but the majority have now fallen into disuse; many are derelict and dry, as groundwater has been diverted for industrial use and the wells no longer reach the water table. Their condition hasn’t been helped by recent dry spells: southern Rajasthan suffered an eight-year drought between 1996 and 2004.

Trong nhiều thế kỷ, hàng ngàn giếng đã được xây dựng trên khắp tây bắc Ấn Độ, nhưng phần lớn hiện đã không được sử dụng; nhiều giếng bị bỏ hoang và khô, vì nước ngầm đã được chuyển hướng để sử dụng trong công nghiệp và các giếng không còn chạm tới mực nước ngầm. Tình trạng của họ đã không được giúp đỡ bởi những đợt hạn hán gần đây: miền nam Rajasthan đã trải qua một đợt hạn hán kéo dài tám năm từ năm 1996 đến năm 2004.

However, some important sites in Gujarat have recently undergone major restoration, and the state government announced in June last year that it plans to restore the stepwells throughout the state.

Tuy nhiên, một số địa điểm quan trọng ở Gujarat gần đây đã trải qua quá trình phục hồi lớn và chính quyền tiểu bang đã thông báo vào tháng 6 năm ngoái rằng họ có kế hoạch khôi phục các giếng bậc thang trên toàn tiểu bang.

In Patan, the state’s ancient capital, the stepwell of Rani Ki Vav (Queen’s Stepwell) is perhaps the finest current example. It was built by Queen Udayamati during the late 11th century, but became silted up following a flood during the 13th century. But the Archaeological Survey of India began restoring it in the 1960s, and today it’s in pristine condition. At 65 metres long, 20 metres wide and 27 metres deep, Rani Ki Vav features 500 distinct sculptures carved into niches throughout the monument, depicting gods such as Vishnu and Parvati in various incarnations. Incredibly, in January 2001, this ancient structure survived a devastating earthquake that measured 7.6 on the Richter scale.

Ở Patan, thủ đô cổ đại của bang, giếng bậc thang của Rani Ki Vav (Queen's Stepwell) có lẽ là ví dụ điển hình nhất hiện nay. Nó được xây dựng bởi Nữ hoàng Udayamati vào cuối thế kỷ 11, nhưng đã trở nên phù sa sau một trận lụt trong thế kỷ 13. Nhưng Khảo sát Khảo cổ học Ấn Độ đã bắt đầu khôi phục nó vào những năm 1960, và ngày nay nó ở trong tình trạng nguyên sơ. Với chiều dài 65 mét, rộng 20 mét và sâu 27 mét, Rani Ki Vav có 500 tác phẩm điêu khắc riêng biệt được chạm khắc vào các hốc trong suốt di tích, mô tả các vị thần như Vishnu và Parvati trong các hóa thân khác nhau. Thật đáng kinh ngạc, vào tháng 1 năm 2001, cấu trúc cổ xưa này đã sống sót sau một trận động đất tàn khốc có kích thước 7,6 độ Richter.

Another example is the Surya Kund in Modhera, northern Gujarat, next to the Sun Temple, built by King Bhima I in 1026 to honour the sun god Surya. It’s actually a tank (kund means reservoir or pond) rather than a well, but displays the hallmarks of stepwell architecture, including four sides of steps that descend to the bottom in a stunning geometrical formation. The terraces house 108 small, intricately carved shrines between the sets of steps.

Một ví dụ khác là Surya Kund ở Modhera, phía bắc Gujarat, bên cạnh Đền Mặt trời, được Vua Bhima I xây dựng vào năm 1026 để tôn vinh thần mặt trời Surya. Nó thực sự là một bể (kund có nghĩa là hồ chứa hoặc ao) chứ không phải là một cái giếng, nhưng thể hiện các đặc điểm nổi bật của kiến trúc giếng bậc thang, bao gồm bốn mặt của các bậc thang đi xuống đáy trong một sự hình thành hình học tuyệt đẹp. Các bậc thang có 108 ngôi đền nhỏ, được chạm khắc phức tạp giữa các bộ bậc thang.

Rajasthan also has a wealth of wells. The ancient city of Bundi, 200 kilometres south of Jaipur, is renowned for its architecture, including its stepwells. One of the larger examples is Raniji Ki Baori, which was built by the queen of the region, Nathavatji, in 1699. At 46 metres deep, 20 metres wide and 40 metres long, the intricately carved monument is one of 21 baoris commissioned in the Bundi area by Nathavatji.

Rajasthan cũng có rất nhiều giếng. Thành phố cổ Bundi, cách Jaipur 200 km về phía nam, nổi tiếng với kiến trúc, bao gồm cả giếng bậc thang. Một trong những ví dụ lớn hơn là Raniji Ki Baori, được xây dựng bởi nữ hoàng của khu vực, Nathavatji, vào năm 1699. Với độ sâu 46 mét, rộng 20 mét và dài 40 mét, tượng đài được chạm khắc phức tạp là một trong 21 baoris được Nathavatji ủy quyền ở khu vực Bundi.

In the old ruined town of Abhaneri, about 95 kilometres east of Jaipur, is Chand Baori, one of India’s oldest and deepest wells; aesthetically, it’s perhaps one of the most dramatic. Built in around 850 AD next to the temple of Harshat Mata, the baori comprises hundreds of zigzagging steps that run along three of its sides, steeply descending 11 storeys, resulting in a striking geometric pattern when seen from afar. On the fourth side, covered verandas supported by ornate pillars overlook the steps.

Ở thị trấn cổ Abhaneri đổ nát, cách Jaipur khoảng 95 km về phía đông, là Chand Baori, một trong những giếng lâu đời nhất và sâu nhất của Ấn Độ; về mặt thẩm mỹ, nó có lẽ là một trong những nơi ấn tượng nhất. Được xây dựng vào khoảng năm 850 sau Công nguyên bên cạnh ngôi đền Harshat Mata, baori bao gồm hàng trăm bậc thang ngoằn ngoèo chạy dọc theo ba mặt của nó, dốc xuống 11 tầng, dẫn đến một mô hình hình học nổi bật khi nhìn từ xa. Ở phía thứ tư, hiên có mái che được hỗ trợ bởi các cột trang trí công phu nhìn ra các bậc thang.

Still in public use is Neemrana Ki Baori, located just off the Jaipur–Delhi highway. Constructed in around 1700, it’s nine storeys deep, with the last two levels underwater. At ground level, there are 86 colonnaded openings from where the visitor descends 170 steps to the deepest water source.

Vẫn được sử dụng công cộng là Neemrana Ki Baori, nằm ngay gần đường cao tốc Jaipur-Delhi. Được xây dựng vào khoảng năm 1700, nó sâu chín tầng, với hai tầng cuối cùng dưới nước. Ở mặt đất, có 86 lỗ mở hàng cột từ đó du khách đi xuống 170 bậc đến nguồn nước sâu nhất.

Today, following years of neglect, many of these monuments to medieval engineering have been saved by the Archaeological Survey of India, which has recognised the importance of preserving them as part of the country’s rich history. Tourists flock to wells in far-flung corners of northwestern India to gaze in wonder at these architectural marvels from 1,000 years ago, which serve as a reminder of both the ingenuity and artistry of ancient civilisations and of the value of water to human existence.

Ngày nay, sau nhiều năm bị bỏ quên, nhiều di tích về kỹ thuật thời trung cổ này đã được cứu bởi Khảo sát Khảo cổ học Ấn Độ, nơi đã nhận ra tầm quan trọng của việc bảo tồn chúng như một phần của lịch sử phong phú của đất nước. Khách du lịch đổ xô đến các giếng ở những góc xa xôi phía tây bắc Ấn Độ để chiêm ngưỡng những kỳ quan kiến trúc kỳ diệu này từ 1.000 năm trước, như một lời nhắc nhở về cả sự khéo léo và nghệ thuật của các nền văn minh cổ đại và giá trị của nước đối với sự tồn tại của con người.

C10 T1 P2 EUROPEAN TRANSPORT SYSTEMS 1990-2010

What have been the trends and what are the prospects for European transport systems?

It is difficult to conceive of vigorous economic growth without an efficient transport system. Although modern information technologies can reduce the demand for physical transport by facilitating teleworking and teleservices, the requirement for transport continues to increase. There are two key factors behind this trend. For passenger transport, the determining factor is the spectacular growth in car use. The number of cars on European Union (EU) roads saw an increase of three million cars each year from 1990 to 2010, and in the next decade the EU will see a further substantial increase in its fleet.

As far as goods transport is concerned, growth is due to a large extent to changes in the European economy and its system of production. In the last 20 years, as internal frontiers have been abolished, the EU has moved from a ‘stock’ economy to a ‘flow’ economy. This phenomenon has been emphasised by the relocation of some industries, particularly those which are labour intensive, to reduce production costs, even though the production site is hundreds or even thousands of kilometres away from the final assembly plant or away from users.

The strong economic growth expected in countries which are candidates for entry to the EU will also increase transport flows, in particular road haulage traffic. In 1998, some of these countries already exported more than twice their 1990 volumes and imported more than five times their 1990 volumes. And although many candidate countries inherited a transport system which encourages rail, the distribution between modes has tipped sharply in favour of road transport since the 1990s. Between 1990 and 1998, road haulage increased by 19.4%, while during the same period rail haulage decreased by 43.5%, although – and this could benefit the enlarged EU – it is still on average at a much higher level than in existing member states.

However, a new imperative-sustainable development – offers an opportunity for adapting the EU’s common transport policy. This objective, agreed by the Gothenburg European Council, has to be achieved by integrating environmental considerations into Community policies, and shifting the balance between modes of transport lies at the heart of its strategy. The ambitious objective can only be fully achieved by 2020, but proposed measures are nonetheless a first essential step towards a sustainable transport system which will ideally be in place in 30 years‟ time, that is by 2040.

In 1998, energy consumption in the transport sector was to blame for 28% of emissions of CO2, the leading greenhouse gas. According to the latest estimates, if nothing is done to reverse the traffic growth trend, CO2 emissions from transport can be expected to increase by around 50% to 1,113 billion tonnes by 2020，compared with the 739 billion tonnes recorded in 1990. Once again, road transport is the main culprit since it alone accounts for 84% of the CO2 emissions attributable to transport. Using alternative fuels and improving energy efficiency is thus both an ecological necessity and a technological challenge.

At the same time greater efforts must be made to achieve a modal shift. Such a change cannot be achieved overnight, all the less so after over half a century of constant deterioration in favour of road. This has reached such a pitch that today rail freight services are facing marginalisation, with just 8% of market share, and with international goods trains struggling along at an average speed of 18km/h. Three possible options have emerged.

The first approach would consist of focusing on road transport solely through pricing. This option would not be accompanied by complementary measures in the other modes of transport. In the short term it might curb the growth in road transport through the better loading ratio of goods vehicles and occupancy rates of passenger vehicles expected as a result of the increase in the price of transport. However, the lack of measures available to revitalise other modes of transport would make it impossible for more sustainable modes of transport to take up the baton.

The second approach also concentrates on road transport pricing but is accompanied by measures to increase the efficiency of the other modes (better quality of services, logistics, technology). However, this approach does not include investment in new infrastructure, nor does it guarantee better regional cohesion. It could help to achieve greater uncoupling than the first approach, but road transport would keep the lion’s share of the market and continue to concentrate on saturated arteries, despite being the most polluting of the modes. It is therefore not enough to guarantee the necessary shift of the balance.

The third approach, which is not new, comprises a series of measures ranging from pricing to revitalising alternative modes of transport and targeting investment in the trans-European network. This integrated approach would allow the market shares of the other modes to return to their 1998 levels and thus make a shift of balance. It is far more ambitious than it looks, bearing in mind the historical imbalance in favour of roads for the last fifty years, but would achieve a marked break in the link between road transport growth and economic growth, without placing restrictions on the mobility of people and goods.

C10 T1 P3 The psychology of innovation

Why are so few companies truly innovative?

Innovation is key to business survival, and companies put substantial resources into inspiring employees to develop new ideas. There are, nevertheless, people working in luxurious, state-of-the-art centres designed to stimulate innovation who find that their environment doesn’t make them feel at all creative. And there are those who don’t have a budget, or much space, but who innovate successfully.

For Robert B. Ciaidini, Professor of Psychology at Arizona State University, one reason that companies don’t succeed as often as they should is that innovation starts with recruitment. Research shows that the fit between an employee’s values and a company’s values makes a difference to what contribution they make and whether, two years after they join, they’re still at the company. Studies at Harvard Business School show that, although some individuals may be more creative than others, almost every individual can be creative in the right circumstances.

One of the most famous photographs in the story of rock’n’roll emphasises Ciaidini’s views. The 1956 picture of singers Elvis Presley, Carl Perkins, Johnny Cash and Jerry Lee Lewis jamming at a piano in Sun Studios in Memphis tells a hidden story. Sun’s ‘million-dollar quartet’ could have been a quintet. Missing from the picture is Roy Orbison, a greater natural singer than Lewis, Perkins or Cash. Sam Phillips, who owned Sun, wanted to revolutionise popular music with songs that fused black and white music, and country and blues. Presley, Cash, Perkins and Lewis instinctively understood Phillips’s ambition and believed in it. Orbison wasn’t inspired by the goal, and only ever achieved one hit with the Sun label.

The value fit matters, says Ciaidini, because innovation is, in part, a process of change, and under that pressure we, as a species, behave differently, ‘When things change, we are hard-wired to play it safe.’ Managers should therefore adopt an approach that appears counterintuitive -they should explain what stands to be lost if the company fails to seize a particular opportunity. Studies show that we invariably take more gambles when threatened with a loss than when offered a reward.

Managing innovation is a delicate art. It’s easy for a company to be pulled in conflicting directions as the marketing, product development, and finance departments each get different feedback from different sets of people. And without a system which ensures collaborative exchanges within the company, it’s also easy for small ‘pockets of innovation’ to disappear. Innovation is a contact sport. You can’t brief people just by saying, ‘We’re going in this direction and I’m going to take you with me.’

Ciaidini believes that this ‘follow-the-leader syndrome, is dangerous, not least because it encourages bosses to go it alone. ‘It’s been scientifically proven that three people will be better than one at solving problems, even if that one person is the smartest person in the field.’ To prove his point, Ciaidini cites an interview with molecular biologist James Watson. Watson, together with Francis Crick, discovered the structure of DNA, the genetic information carrier of all living organisms. ‘When asked how they had cracked the code ahead of an array of highly accomplished rival investigators, he said something that stunned me. He said he and Crick had succeeded because they were aware that they weren’t the most intelligent of the scientists pursuing the answer. The smartest scientist was called Rosalind Franklin who, Watson said, “was so intelligent she rarely sought advice”.’

Teamwork taps into one of the basic drivers of human behaviour. ‘The principle of social proof is so pervasive that we don’t even recognise it,’ says Ciaidini. ‘If your project is being resisted, for example, by a group of veteran employees, ask another old-timer to speak up for it.’ Ciaidini is not alone in advocating this strategy. Research shows that peer power, used horizontally not vertically, is much more powerful than any boss’s speech.

Writing, visualising and prototyping can stimulate the flow of new ideas. Ciaidini cites scores of research papers and historical events that prove that even something as simple as writing deepens every individual’s engagement in the project. It is, he says, the reason why all those competitions on breakfast cereal packets encouraged us to write in saying, in no more than 10 words: ‘I like Kellogg’s Corn Flakes because… .’ The very act of writing makes us more likely to believe it.

Authority doesn’t have to inhibit innovation but it often does. The wrong kind of leadership will lead to what Ciaidini calls ‘captainitis, the regrettable tendency of team members to opt out of team responsibilities that are properly theirs’. He calls it captainitis because, he says, ‘crew members of multipilot aircraft exhibit a sometimes deadly passivity when the flight captain makes a clearly wrong-headed decision’. This behaviour is not, he says, unique to air travel, but can happen in any workplace where the leader is overbearing.

At the other end of the scale is the 1980s Memphis design collective, a group of young designers for whom ‘the only rule was that there were no rule’. This environment encouraged a free interchange of ideas, which led to more creativity with form, function, colour and materials that revolutionised attitudes to furniture design.

Many theorists believe the ideal boss should lead from behind, taking pride in collective accomplishment and giving credit where it is due. Ciaidini says: ‘Leaders should encourage everyone to contribute and simultaneously assure all concerned that every recommendation is important to making the right decision and will be given full attention.’ The frustrating thing about innovation is that there are many approaches, but no magic formula. However, a manager who wants to create a truly innovative culture can make their job a lot easier by recognising these psychological realities.

C10 T2 P1 Tea and the Industrial Revolution

A Cambridge professor says that a change in drinking habits was the reason for the Industrial Revolution in Britain. Anjana Abuja reports

Alan Macfarlane, professor of anthropological science at King’s College, Cambridge has, like other historians, spent decades wrestling with the enigma of the Industrial Revolution. Why did this particular Big Bang – the world-changing birth of industry-happen in Britain? And why did it strike at the end of the 18th century?

Macfarlane compares the puzzle to a combination lock. ‘There are about 20 different factors and all of them need to be present before the revolution can happen,’ he says. For industry to take off, there needs to be the technology and power to drive factories, large urban populations to provide cheap labour, easy transport to move goods around, an affluent middle-class willing to buy mass-produced objects, a market-driven economy and a political system that allows this to happen. While this was the case for England, other nations, such as Japan, the Netherlands and France also met some of these criteria but were not industrialising. All these factors must have been necessary. But not sufficient to cause the revolution, says Macfarlane. ‘After all, Holland had everything except coal while China also had many of these factors. Most historians are convinced there are one or two missing factors that you need to open the lock.’

The missing factors, he proposes, are to be found in almost even kitchen cupboard. Tea and beer, two of the nation’s favourite drinks, fuelled the revolution. The antiseptic properties of tannin, the active ingredient in tea, and of hops in beer – plus the fact that both are made with boiled water – allowed urban communities to flourish at close quarters without succumbing to water-borne diseases such as dysentery. The theory sounds eccentric but once he starts to explain the detective work that went into his deduction, the scepticism gives way to wary admiration. Macfarlanes case has been strengthened by support from notable quarters – Roy Porter, the distinguished medical historian, recently wrote a favourable appraisal of his research.

Macfarlane had wondered for a long time how the Industrial Revolution came about. Historians had alighted on one interesting factor around the mid-18th century that required explanation. Between about 1650 and 1740, the population in Britain was static. But then there was a burst in population growth. Macfarlane says: ‘The infant mortality rate halved in the space of 20 years, and this happened in both rural areas and cities, and across all classes. People suggested four possible causes. Was there a sudden change in the viruses and bacteria around? Unlikely. Was there a revolution in medical science? But this was a century before Lister’s revolution*. Was there a change in environmental conditions? There were improvements in agriculture that wiped out malaria, but these were small gains. Sanitation did not become widespread until the 19th century. The only option left is food. But the height and weight statistics show a decline. So the food must have got worse. Efforts to explain this sudden reduction in child deaths appeared to draw a blank.’

This population burst seemed to happen at just the right time to provide labour for the Industrial Revolution. ‘When you start moving towards an industrial revolution, it is economically efficient to have people living close together,’ says Macfarlane. ‘But then you get diseases, particularly from human waste.’ Some digging around in historical records revealed that there was a change in the incidence of water-borne disease at that time, especially dysentery. Macfarlane deduced that whatever the British were drinking must have been important in regulating disease. He says, ‘We drank beer. For a long time, the English were protected by the strong antibacterial agent in hops, which were added to help preserve the beer. But in the late 17th century a tax was introduced on malt, the basic ingredient of beer. The poor turned to water and gin and in the 1720s the mortality rate began to rise again. Then it suddenly dropped again. What caused this?’

Macfarlane looked to Japan, which was also developing large cities about the same time, and also had no sanitation. Water-borne diseases had a much looser grip on the Japanese population than those in Britain. Could it be the prevalence of tea in their culture? Macfarlane then noted that the history of tea in Britain provided an extraordinary coincidence of dates. Tea was relatively expensive until Britain started a direct clipper trade with China in the early 18th century. By the 1740s, about the time that infant mortality was dipping, the drink was common. Macfarlane guessed that the fact that water had to be boiled, together with the stomach-purifying properties of tea meant that the breast milk provided by mothers was healthier than it had ever been. No other European nation sipped tea like the British, which, by Macfarlanes logic, pushed these other countries out of contention for the revolution.

But, if tea is a factor in the combination lock, why didn’t Japan forge ahead in a tea-soaked industrial revolution of its own? Macfarlane notes that even though 17th-century Japan had large cities, high literacy rates, even a futures market, it had turned its back on the essence of any work-based revolution by giving up labour-saving devices such as animals, afraid that they would put people out of work. So, the nation that we now think of as one of the most technologically advanced entered the 19th century having ‘abandoned the wheel’.

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* Joseph Lister was the first doctor to use antiseptic techniques during surgical operations to prevent infections.

C10 T2 P2 Gifted children and learning

Internationally, ‘giftedness’ is most frequently determined by a score on a general intelligence test, known as an IQ test, which is above a chosen cutoff point, usually at around the top 2-5%. Children’s educational environment contributes to the IQ score and the way intelligence is used. For example, a very close positive relationship was found when children’s IQ scores were compared with their home educational provision (Freeman, 2010). The higher the children’s IQ scores, especially over IQ 130, the better the quality of their educational backup, measured in terms of reported verbal interactions with parents, number of books and activities in their home etc. Because IQ tests are decidedly influenced by what the child has learned, they are to some extent measures of current achievement based on age-norms; that is, how well the children have learned to manipulate their knowledge and know-how within the terms of the test. The vocabulary aspect, for example, is dependent on having heard those words. But IQ tests can neither identify the processes of learning and thinking nor predict creativity.

Excellence does not emerge without appropriate help. To reach an exceptionally high standard in any area very able children need the means to learn, which includes material to work with and focused challenging tuition -and the encouragement to follow their dream. There appears to be a qualitative difference in the way the intellectually highly able think, compared with more average-ability or older pupils, for whom external regulation by the teacher often compensates for lack of internal regulation. To be at their most effective in their self-regulation, all children can be helped to identify their own ways of learning – metacognition – which will include strategies of planning, monitoring, evaluation, and choice of what to learn. Emotional awareness is also part of metacognition, so children should be helped to be aware of their feelings around the area to be learned, feelings of curiosity or confidence, for example.

High achievers have been found to use self-regulatory learning strategies more often and more effectively than lower achievers, and are better able to transfer these strategies to deal with unfamiliar tasks. This happens to such a high degree in some children that they appear to be demonstrating talent in particular areas. Overviewing research on the thinking process of highly able children, (Shore and Kanevsky, 1993) put the instructor’s problem succinctly: ‘If they [the gifted] merely think more quickly, then .we need only teach more quickly. If they merely make fewer errors, then we can shorten the practice’. But of course, this is not entirely the case; adjustments have to be made in methods of learning and teaching, to take account of the many ways individuals think.

Yet in order to learn by themselves, the gifted do need some support from their teachers. Conversely, teachers who have a tendency to ‘overdirect’ can diminish their gifted pupils’ learning autonomy. Although ‘spoon-feeding’ can produce extremely high examination results, these are not always followed by equally impressive life successes. Too much dependence on the teachers risks loss of autonomy and motivation to discover. However, when teachers help pupils to reflect on their own learning and thinking activities, they increase their pupils’ self-regulation. For a young child, it may be just the simple question ‘What have you learned today?’ which helps them to recognise what they are doing. Given that a fundamental goal of education is to transfer the control of learning from teachers to pupils, improving pupils’ learning to learn techniques should be a major outcome of the school experience, especially for the highly competent. There are quite a number of new methods which can help, such as child- initiated learning, ability-peer tutoring, etc. Such practices have been found to be particularly useful for bright children from deprived areas.

But scientific progress is not all theoretical, knowledge is a so vital to outstanding performance: individuals who know a great deal about a specific domain will achieve at a higher level than those who do not (Elshout, 1995). Research with creative scientists by Simonton (1988) brought him to the conclusion that above a certain high level, characteristics such as independence seemed to contribute more to reaching the highest levels of expertise than intellectual skills, due to the great demands of effort and time needed for learning and practice. Creativity in all forms can be seen as expertise mixed with a high level of motivation (Weisberg, 1993).

To sum up, learning is affected by emotions of both the individual and significant others. Positive emotions facilitate the creative aspects of learning and negative emotions inhibit it. Fear, for example, can limit the development of curiosity, which is a strong force in scientific advance, because it motivates problem-solving behaviour. In Boekaerts’ (1991) review of emotion the learning of very high IQ and highly achieving children, she found emotional forces in harness. They were not only curious, but often had a strong desire to control their environment, improve their learning efficiency and increase their own learning resources.

C10 T2 P3 Museums of fine art and their public

The fact that people go to the Louvre museum in Paris to see the original painting Mona Lisa when they can see a reproduction anywhere leads us to question some assumptions about the role of museums of fine art in today’s world

Thực tế rằng mọi người đến bảo tàng Louvre ở Paris để xem bức tranh Mona Lisa bản gốc, trong khi họ có thể xem bản sao ở bất cứ đâu, khiến chúng ta phải đặt câu hỏi về một số quan niệm về vai trò của các bảo tàng mỹ thuật trong thế giới ngày nay.

One of the most famous works of art in the world is Leonardo da Vinci’s Mona Lisa. Nearly everyone who goes to see the original will already be familiar with it from reproductions, but they accept that fine art is more rewardingly viewed in its original form.

Hầu như mọi người đến xem bản gốc đều đã quen thuộc với bức tranh này thông qua các bản sao, nhưng họ chấp nhận rằng các tác phẩm mỹ thuật sẽ được thưởng thức trọn vẹn hơn khi được xem ở dạng bản gốc.

However, if Mona Lisa was a famous novel, few people would bother to go to a museum to read the writer’s actual manuscript rather than a printed reproduction. This might be explained by the fact that the novel has evolved precisely because of technological developments that made it possible to print out huge numbers of texts, whereas oil paintings have always been produced as unique objects. In addition, it could be argued that the practice of interpreting or ‘reading’ each medium follows different conventions. With novels, the reader attends mainly to the meaning of words rather than the way they are printed on the page, whereas the ‘reader’ of a painting must attend just as closely to the material form of marks and shapes in the picture as to any ideas they may signify.

Tuy nhiên, nếu Mona Lisa là một cuốn tiểu thuyết nổi tiếng thì rất ít người sẽ đến bảo tàng chỉ để đọc bản thảo gốc của tác giả thay vì đọc một bản in. Điều này có thể được giải thích bởi thực tế rằng tiểu thuyết đã phát triển chính nhờ những tiến bộ công nghệ cho phép in ra số lượng lớn văn bản, trong khi tranh sơn dầu luôn được tạo ra như những tác phẩm độc nhất. Ngoài ra, cũng có thể cho rằng cách diễn giải hay “đọc” mỗi loại hình nghệ thuật tuân theo những quy ước khác nhau. Đối với tiểu thuyết, người đọc chủ yếu chú ý đến ý nghĩa của từ ngữ chứ không phải cách chúng được in trên trang giấy. Ngược lại, khi “đọc” một bức tranh, người xem phải chú ý kỹ không chỉ đến những ý tưởng mà bức tranh thể hiện mà còn đến hình thức vật chất của các nét vẽ và hình dạng trong bức tranh.

Yet it has always been possible to make very accurate facsimiles of pretty well any fine art work. The seven surviving versions of Mona Lisa bear witness to the fact that in the 16th century, artists seemed perfectly content to assign the reproduction of their creations to their workshop apprentices as regular ‘bread and butter’ work. And today the task of reproducing pictures is incomparably more simple and reliable, with reprographic techniques that allow the production of high-quality prints made exactly to the original scale, with faithful colour values, and even with duplication of the surface relief of the painting.

But despite an implicit recognition that the spread of good reproductions can be culturally valuable, museums continue to promote the special status of original work.

Unfortunately, this seems to place severe limitations on the kind of experience offered to visitors.

One limitation is related to the way the museum presents its exhibits. As repositories of unique historical objects, art museums are often called ‘treasure houses’. We are reminded of this even before we view a collection by the presence of security guards, attendants, ropes and display cases to keep us away from the exhibits. In many cases, the architectural style of the building further reinforces that notion. In addition, a major collection like that of London’s National Gallery is housed in numerous rooms, each with dozens of works, any one of which is likely to be worth more than all the average visitor possesses. In a society that judges the personal status of the individual so much by their material worth, it is therefore difficult not to be impressed by one’s own relative ‘worthlessness’ in such an environment.

Furthermore, consideration of the ‘value’ of the original work in its treasure house setting impresses upon the viewer that, since these works were originally produced, they have been assigned a huge monetary value by some person or institution more powerful than themselves. Evidently, nothing the viewer thinks about the work is going to alter that value, and so today’s viewer is deterred from trying to extend that spontaneous, immediate, self-reliant kind of reading which would originally have met the work.

The visitor may then be struck by the strangeness of seeing such diverse paintings, drawings and sculptures brought together in an environment for which they were not originally created. This ‘displacement effect’ is further heightened by the sheer volume of exhibits. In the case of a major collection, there are probably more works on display than we could realistically view in weeks or even months.

This is particularly distressing because time seems to be a vital factor in the appreciation of all art forms. A fundamental difference between paintings and other art forms is that there is no prescribed time over which a painting is viewed. By contrast, the audience encourage an opera or a play over a specific time, which is the duration of the performance. Similarly novels and poems are read in a prescribed temporal sequence, whereas a picture has no clear place at which to start viewing, or at which to finish. Thus art works themselves encourage us to view them superficially, without appreciating the richness of detail and labour that is involved.

Consequently, the dominant critical approach becomes that of the art historian, a specialised academic approach devoted to ‘discovering the meaning’ of art within the cultural context of its time. This is in perfect harmony with the museum s function, since the approach is dedicated to seeking out and conserving ‘authentic’, original, readings of the exhibits. Again, this seems to put paid to that spontaneous, participators criticism which can be found in abundance in criticism of classic works of literature, but is absent from most art history.

The displays of art museums serve as a warning of what critical practices can emerge when spontaneous criticism is suppressed. The museum public, like any other audience, experience art more rewardingly when given the confidence to express their views. If appropriate works of fine art could be rendered permanently accessible to the public by means of high-fidelity reproductions, as literature and music already are, the public may feel somewhat less in awe of them. Unfortunately, that may be too much to ask from those who seek to maintain and control the art establishment.

C10 T3 P1 The Context, Meaning and Scope of Tourism

Travel has existed since the beginning of time, when primitive man set out, often traversing great distances in search of game, which provided the food and clothing necessary for his survival. Throughout the course of history, people have travelled for purposes of trade, religious conviction, economic gain, war, migration and other equally compelling motivations. In the Roman era, wealthy aristocrats and high government officials also travelled for pleasure. Seaside resorts located at Pompeii and Herculaneum afforded citizens the opportunity to escape to their vacation villas in order to avoid the summer heat of Rome. Travel, except during the Dark Ages, has continued to grow and, throughout recorded history, has played a vital role in the development of civilisations and their economies.

Tourism in the mass form as we know it today is a distinctly twentieth-century phenomenon. Historians suggest that the advent of mass tourism began in England during the industrial revolution with the rise of the middle class and the availability of relatively inexpensive transportation. The creation of the commercial airline industry following the Second World War and the subsequent development of the jet aircraft in the 1950s signalled the rapid growth and expansion of international travel. This growth led to the development of a major new industry: tourism. In turn, international tourism became the concern of a number of world governments since it not only provided new employment opportunities but also produced a means of earning foreign exchange.

Tourism today has grown significantly in both economic and social importance. In most industrialised countries over the past few years the fastest growth has been seen in the area of services. One of the largest segments of the service industry, although largely unrecognised as an entity in some of these countries, is travel and tourism. According to the World Travel and Tourism Council (1992), Travel and tourism is the largest industry in the world on virtually any economic measure including value-added capital investment, employment and tax contributions. In 1992 ‘the industry’s gross output was estimated to be $3.5 trillion, over 12 per cent of all consumer spending. The travel and tourism industry is the world’s largest employer the almost 130 million jobs, or almost 7 per cent of all employees. This industry is the world’s leading industrial contributor, producing over 6 per cent of the world’s national product and accounting for capital investment in excess of $422 billion m direct indirect and personal taxes each year. Thus, tourism has a profound impact both on the world economy and, because of the educative effect of travel and the effects on employment, on society itself.

However, the major problems of the travel and tourism industry that have hidden, or obscured, its economic impact are the diversity and fragmentation of the industry itself. The travel industry includes: hotels, motels and other types of accommodation; restaurants and other food services; transportation services and facilities; amusements, attractions and other leisure facilities; gift shops and a large number of other enterprises. Since many of these businesses also serve local residents, the impact of spending by visitors can easily be overlooked or underestimated. In addition, Meis (1992) points out that the tourism industry involves concepts that have remained amorphous to both analysts and decision makers. Moreover, in all nations this problem has made it difficult for the industry to develop any type of reliable or credible tourism information base in order to estimate the contribution it makes to regional, national and global economies. However, the nature of this very diversity makes travel and tourism ideal vehicles for economic development in a wide variety of countries, regions or communities.

Once the exclusive province of the wealthy, travel and tourism have become an institutionalised way of life for most of the population. In fact, McIntosh and Goeldner (1990) suggest that tourism has become the largest commodity in international trade for many nations and, for a significant number of other countries, it ranks second or third. For example, tourism is the major source of income in Bermuda, Greece, Italy, Spain, Switzerland and most Caribbean countries. In addition, Hawkins and Ritchie, quoting from data published by the American Express Company, suggest that the travel and tourism industry is the number one ranked employer in the Bahamas, Brazil, Canada, France, (the former) West Germany, Hong Kong, Italy, Jamaica, Japan, Singapore, the United Kingdom and the United States. However, because of problems of definition, which directly affect statistical measurement, it is not possible with any degree of certainty to provide precise, valid or reliable data about the extent of world-wide tourism participation or its economic impact. In many cases, similar difficulties arise when attempts are made to measure domestic tourism.

C10 T3 P2 Autumn leaves

Canadian writer Jay Ingram investigates the mystery of why leaves turn red in the fall

One of the most captivating natural events of the year in many areas throughout North America is the turning of the leaves in the fall. The colours are magnificent, but the question of exactly why some trees turn yellow or orange, and others red or purple, is something which has long puzzled scientists.

Summer leaves are green because they are full of chlorophyll, the molecule that captures sunlight converts that energy into new building materials for the tree. As fall approaches in the northern hemisphere, the amount of solar energy available declines considerably. For many trees – evergreen conifers being an exception – the best strategy is to abandon photosynthesis* until the spring. So rather than maintaining the now redundant leaves throughout the winter, the tree saves its precious resources and discards them. But before letting its leaves go, the tree dismantles their chlorophyll molecules and ships their valuable nitrogen back into the twigs. As chlorophyll is depleted, other colours that have been dominated by it throughout the summer begin to be revealed. This unmasking explains the autumn colours of yellow and orange, but not the brilliant reds and purples of trees such as the maple or sumac.

The source of the red is widely known: it is created by anthocyanins, water-soluble plant pigments reflecting the red to blue range of the visible spectrum. They belong to a class of sugar-based chemical compounds also known as flavonoids. What’s puzzling is that anthocyanins are actually newly minted, made in the leaves at the same time as the tree is preparing to drop them. But it is hard to make sense of the manufacture of anthocyanins – why should a tree bother making new chemicals in its leaves when it’s already scrambling to withdraw and preserve the ones already there?

Some theories about anthocyanins have argued that they might act as a chemical defence against attacks by insects or fungi, or that they might attract fruit-eating birds or increase a leafs tolerance to freezing. However there are problems with each of these theories, including the fact that leaves are red for such a relatively short period that the expense of energy needed to manufacture the anthocyanins would outweigh any anti-fungal or anti-herbivore activity achieved.

It has also been proposed that trees may produce vivid red colours to convince herbivorous insects that they are healthy and robust and would be easily able to mount chemical defences against infestation. If insects paid attention to such advertisements, they might be prompted to lay their eggs on a duller, and presumably less resistant host. The flaw in this theory lies in the lack of proof to support it. No one has as yet ascertained whether more robust trees sport the brightest leaves, or whether insects make choices according to colour intensity.

Perhaps the most plausible suggestion as to why leaves would go to the trouble of making anthocyanins when they’re busy packing up for the winter is the theory known as the ‘light screen’ hypothesis. It sounds paradoxical, because the idea behind this hypothesis is that the red pigment is made in autumn leaves to protect chlorophyll, the light-absorbing chemical, from too much light. Why does chlorophyll need protection when it is the natural world’s supreme light absorber? Why protect chlorophyll at a time when the tree is breaking it down to salvage as much of it as possible?

Chlorophyll, although exquisitely evolved to capture the energy of sunlight, can sometimes be overwhelmed by it, especially in situations of drought, low temperatures, or nutrient deficiency. Moreover, the problem of oversensitivity to light is even more acute in the fall, when the leaf is busy preparing for winter by dismantling its internal machinery. The energy absorbed by the chlorophyll molecules of the unstable autumn leaf is not immediately channelled into useful products and processes, as it would be in an intact summer leaf. The weakened fall leaf then becomes vulnerable to the highly destructive effects of the oxygen created by the excited chlorophyll molecules.

Even if you had never suspected that this is what was going on when leaves turn red, there are clues out there. One is straightforward: on many trees, the leaves that are the reddest are those on the side of the tree which gets most sun. Not only that, but the red is brighter on the upper side of the leaf. It has also been recognised for decades that the best conditions for intense red colours are dry, sunny days and cool nights, conditions that nicely match those that make leaves susceptible to excess light. And finally, trees such as maples usually get much redder the more north you travel in the northern hemisphere. It’s colder there, they’re more stressed, their chlorophyll is more sensitive and it needs more sunblock.

What is still not fully understood, however, is why some trees resort to producing red pigments while others don’t bother, and simply reveal their orange or yellow hues. Do these trees have other means at their disposal to prevent overexposure to light in autumn? Their story, though not as spectacular to the eye, will surely turn out to be as subtle and as complex.

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* photosynthesis: the production of new material from sunlight, water and carbon dioxide.

C10 T3 P3 Beyond the blue horizon

Ancient voyagers who settled the far-flung islands of the Pacific Ocean

An important archaeological discovery on the island of Efate in the Pacific archipelago of Vanuatu has revealed traces of an ancient seafaring people, the distant ancestors of today’s Polynesians. The site came to light only by chance. An agricultural worker, digging in the grounds of a derelict plantation, scraped open a grave – the first of dozens in a burial ground some 3,000 years old. It is the oldest cemetery ever found in the Pacific islands, and it harbors the remains of an ancient people archaeologists call the Lapita.

They were daring blue-water adventurers who used basic canoes to rove across the ocean. But they were not just explorers. They were also pioneers who carried with them everything they would need to build new lives – their livestock, taro seedlings and stone tools. Within the span of several centuries, the Lapita stretched the boundaries of their world from the jungle-clad volcanoes of Papua New Guinea to the loneliest coral outliers of Tonga.

The Lapita left precious few clues about themselves, but Efate expands the volume of data available to researchers dramatically. The remains of 62 individuals have been uncovered so far, and archaeologists were also thrilled to find six complete Lapita pots. Other items included a Lapita burial urn with modeled birds arranged on the rim as though peering down at the human remains sealed inside. ‘It’s an important discovery,’ says Matthew Spriggs, professor of archaeology at the Australian National University and head of the international team digging up the site, ‘for it conclusively identifies the remains as Lapita.’

DNA teased from these human remains may help answer one of the most puzzling questions in Pacific anthropology: did all Pacific islanders spring from one source or many? Was there only one outward migration from a single point in Asia, or several from different points? ‘This represents the best opportunity we’ve had yet,’ says Spriggs, ‘to find out who the Lapita actually were, where they came from, and who their closest descendants are today.’

There is one stubborn question for which archaeology has yet to provide any answers: how did the Lapita accomplish the ancient equivalent of a moon landing, many times over? No-one has found one of their canoes or any rigging, which could reveal how the canoes were sailed. Nor do the oral histories and traditions of later Polynesians offer any insights, for they turn into myths long before they reach as far back in time as the Lapita.

‘All we can say for certain is that the Lapita had canoes that were capable of ocean voyages, and they had the ability to sail them,’ says Geoff Irwin, a professor of archaeology at the University of Auckland. Those sailing skills, he says, were developed and passed down over thousands of years by earlier mariners who worked their way through the archipelagoes of the western Pacific, making short crossings to nearby islands. The real adventure didn’t begin, however, until their Lapita descendants sailed out of sight of land, with empty horizons on every side. This must have been as difficult for them as landing on the moon is for us today. Certainly it distinguished them from their ancestors, but what gave them the courage to launch out on such risky voyages?

The Lap it as thrust into the Pacific was eastward, against the prevailing trade winds, Irwin notes. Those nagging headwinds, he argues, may have been the key to their success. ‘They could sail out for days into the unknown and assess the area, secure in the knowledge that if they didn’t find anything, they could turn about and catch a swift ride back on the trade winds. This is what would have made the whole thing work.’ Once out there, skilled seafarers would have detected abundant leads to follow to land: seabirds, coconuts and twigs carried out to sea by the tides, and the afternoon pile-up of clouds on the horizon which often indicates an island in the distance.

For returning explorers, successful or not, the geography of their own archipelagoes would have provided a safety net. Without this to go by, overshooting their home ports, getting lost and sailing off into eternity would have been all too easy. Vanuatu, for example, stretches more than 500 miles in a northwest-southeast trend, its scores of intervisible islands forming a backstop for mariners riding the trade winds home.

All this presupposes one essential detail, says Atholl Anderson, professor of prehistory at the Australian National University: the Lapita had mastered the advanced art of sailing against the wind. ‘And there’s no proof they could do any such thing,’ Anderson says. ‘There has been this assumption they did, and people have built canoes to re-create those early voyages based on that assumption. But nobody has any idea what their canoes looked like or how they were rigged.’

Rather than give all the credit to human skill, Anderson invokes the winds of chance. El Nino, the same climate disruption that affects the Pacific today, may have helped scatter the Lapita, Anderson suggests. He points out that climate data obtained from slow-growing corals around the Pacific indicate a series of unusually frequent El Ninos around the time of the Lapita expansion. By reversing the regular east-to-west flow of the trade winds for weeks at a time, these super El Ninos might have taken the Lapita on long unplanned voyages.

However they did it, the Lapita spread themselves a third of the way across the Pacific, then called it quits for reasons known only to them. Ahead lay the vast emptiness of the central Pacific and perhaps they were too thinly stretched to venture farther. They probably never numbered more than a few thousand in total, and in their rapid migration eastward they encountered hundreds of islands – more than 300 in Fiji alone.

C10 T4 P1 The megafires of California

Drought, housing expansion, and oversupply of tinder make for bigger, hotter fires in the western United States

Hạn hán, sự mở rộng nhà ở và việc cung cấp quá nhiều bùi nhùi tạo ra những đám cháy lớn hơn, nóng hơn ở miền tây Hoa Kỳ

Wildfires are becoming an increasing menace in the western United States, with Southern California being the hardest hit area. There’s a reason fire squads battling more frequent blazes in Southern California are having such difficulty containing the flames, despite better preparedness than ever and decades of experience fighting fires fanned by the ‘Santa Ana Winds’. The wildfires themselves, experts say, are generally hotter, faster, and spread more erratically than in the past.

Cháy rừng đang trở thành mối đe dọa ngày càng tăng ở miền Tây Hoa Kỳ, với Nam California là khu vực bị ảnh hưởng nặng nề nhất. Có một lý do khiến các đội cứu hỏa đang chiến đấu với những đám cháy thường xuyên hơn ở Nam California gặp khó khăn đến thế trong việc dập tắt ngọn lửa, mặc dù đã chuẩn bị tốt hơn bao giờ hết với hàng chục năm kinh nghiệm chữa cháy là do 'Những cơn gió Santa Ana' thổi bùng. Các chuyên gia cho biết bản thân các vụ cháy rừng thường nóng hơn, nhanh hơn và lan rộng thất thường hơn so với trước đây.

Megafires, also called ‘siege fires’, are the increasingly frequent blazes that burn 500,000 acres or more – 10 times the size of the average forest fire of 20 years ago. Some recent wildfires are among the biggest ever in California in terms of acreage burned, according to state figures and news reports.

Megafires, còn được gọi là 'đám cháy vòng vây', là những đám cháy ngày càng trở nên thường xuyên, lan rộng 500.000 mẫu Anh trở lên – gấp 10 lần quy mô của đám cháy rừng trung bình cách đây 20 năm. Một số vụ cháy rừng gần đây là một trong những vụ cháy rừng lớn nhất từ trước đến nay ở California xét về diện tích bị cháy, theo các số liệu và bản tin của tiểu bang.

One explanation for the trend to more superhot fires is that the region, which usually has dry summers, has had significantly below normal precipitation in many recent years. Another reason, experts say, is related to the century- long policy of the US Forest Service to stop wildfires as quickly as possible.

Một lời giải thích cho xu hướng xảy ra nhiều đám cháy siêu nóng hơn là khu vực này - thường có mùa hè khô hạn - đã có lượng mưa thấp hơn đáng kể so với bình thường trong nhiều năm gần đây. Các chuyên gia cho rằng một lý do khác có liên quan đến chính sách kéo dài hàng thế kỷ của Cục Lâm nghiệp Hoa Kỳ nhằm ngăn chặn cháy rừng càng nhanh càng tốt.

The unintentional consequence has been to halt the natural eradication of underbrush, now the primary fuel for megafires.

Hậu quả không chủ ý là ngăn chặn quá trình tiêu diệt tự nhiên của bụi rậm, hiện là nhiên liệu chính cho các đám cháy lớn.

Three other factors contribute to the trend, they add. First is climate change, marked by a 1-degree Fahrenheit rise in average yearly temperature across the western states. Second is fire seasons that on average are 78 days longer than they were 20 years ago. Third is increased construction of homes in wooded areas.

Ba yếu tố khác cũng góp phần tạo ra xu thế này, họ nói thêm. Đầu tiên là biến đổi khí hậu, được đánh dấu bằng việc nhiệt độ trung bình hàng năm tăng 1 độ F trên khắp các bang phía Tây. Thứ hai là mùa cháy kéo dài trung bình nhiều hơn so với 20 năm trước 78 ngày. Thứ ba là tăng cường xây dựng nhà ở trong khu vực nhiều cây cối.

‘We are increasingly building our homes in fire-prone ecosystems,’ says Dominik Kulakowski, adjunct professor of biology at Clark University Graduate School of Geography in Worcester, Massachusetts. ‘Doing that in many of the forests of the western US is like building homes on the side of an active volcano.’

Dominik Kulakowski, phó giáo sư sinh học tại Trường Đại học Địa lý Đại học Clark ở Worcester, Massachusetts, cho biết: “Chúng ta đang ngày càng xây dựng những ngôi nhà của mình trong các hệ sinh thái dễ xảy ra hỏa hoạn. 'Làm điều đó ở nhiều khu rừng ở miền tây Hoa Kỳ giống như xây nhà bên sườn núi lửa đang hoạt động.'

In California, where population growth has averaged more than 600,000 a year for at least a decade, more residential housing is being built. ‘What once was open space is now residential homes providing fuel to make fires burn with greater intensity,’ says Terry McHale of the California Department of Forestry firefighters’ union. ‘With so much dryness, so many communities to catch fire, so many fronts to fight, it becomes an almost incredible job.’

Ở California, nơi dân số tăng trung bình hơn 600.000 người một năm trong ít nhất một thập kỷ, ngày càng có nhiều nhà ở được xây dựng. Terry McHale thuộc hiệp hội lính cứu hỏa của Bộ Lâm nghiệp California cho biết: “Những gì từng là không gian mở giờ là những ngôi nhà dân cư - nhiên liệu cho những đám cháy với cường độ cao hơn. 'Với quá nhiều sự hanh khô, quá nhiều khu cư dân dễ xảy ra hoả hoạn, quá nhiều mặt trận để chiến đấu, việc này gần như ngoài sức tưởng tượng.'

That said, many experts give California high marks for making progress on preparedness in recent years, after some of the largest fires in state history scorched thousands of acres, burned thousands of homes, and killed numerous people. Stung in the past by criticism of bungling that allowed fires to spread when they might have been contained, personnel are meeting the peculiar challenges of neighborhood – and canyon- hopping fires better than previously, observers say.

Dù vậy, nhiều chuyên gia đánh giá cao California vì đã đạt được tiến bộ trong việc chuẩn bị sẵn sàng trong những năm gần đây, sau khi một số đám cháy lớn nhất trong lịch sử tiểu bang đã thiêu rụi hàng nghìn mẫu Anh, thiêu rụi hàng nghìn ngôi nhà và giết chết nhiều người. Từng gặp phải chỉ trích vì để xảy ra sơ suất khiến lửa lan rộng dù đáng ra có thể kiểm soát, các nhân viên đang xử lý những thách thức riêng biệt của các khu dan cư – và các đám cháy vượt hẻm núi tốt hơn trước đây, các nhà quan sát cho biết.

State promises to provide more up-to-date engines, planes, and helicopters to fight fires have been fulfilled. Firefighters’ unions that in the past complained of dilapidated equipment, old fire engines, and insufficient blueprints for fire safety are now praising the state’s commitment, noting that funding for firefighting has increased, despite huge cuts in many other programs. ‘We are pleased that the current state administration has been very proactive in its support of us, and [has] come through with budgetary support of the infrastructure needs we have long sought,’ says Mr. McHale of the firefighters’ union.

Lời hứa của bang về việc cung cấp nhiều động cơ, máy bay và trực thăng hiện đại hơn để chữa cháy đã được thực hiện. Các nghiệp đoàn cứu hỏa trước đây phàn nàn về thiết bị xuống cấp, xe chữa cháy cũ và không đủ bản thiết kế an toàn phòng cháy chữa cháy hiện đang ca ngợi cam kết của tiểu bang, đồng thời lưu ý rằng kinh phí dành cho công tác chữa cháy đã tăng lên, dù cho nhiều chương trình khác đã bị cắt giảm đáng kể. Ông McHale thuộc hiệp hội lính cứu hỏa cho biết: “Chúng tôi hài lòng rằng chính quyền tiểu bang hiện tại đã rất tích cực hỗ trợ chúng tôi và [đã] thông qua hỗ trợ ngân sách cho các nhu cầu cơ sở hạ tầng mà chúng tôi đã tìm kiếm từ lâu”.

Besides providing money to upgrade the fire engines that must traverse the mammoth state and wind along serpentine canyon roads, the state has invested in better command-and-control facilities as well as in the strategies to run them. ‘In the fire sieges of earlier years, we found that other jurisdictions and states were willing to offer mutual-aid help, but we were not able to communicate adequately with them,’ says Kim Zagaris, chief of the state’s Office of Emergency Services Fire and Rescue Branch.

Bên cạnh việc cung cấp tiền để nâng cấp các xe cứu hỏa phải đi khắp tiểu bang khổng lồ này và uốn lượn dọc theo những con đường hẻm núi ngoằn ngoèo, bang đã đầu tư vào các cơ sở chỉ huy và kiểm soát tốt hơn cũng như các chiến lược để vận hành chúng. Kim Zagaris, giám đốc Văn phòng Dịch vụ Cứu hỏa Khẩn cấp của bang cho biết: “Trong các đám cháy vòng vây những năm trước, chúng tôi nhận thấy rằng các khu vực pháp lý và tiểu bang khác sẵn sàng hỗ trợ lẫn nhau, nhưng chúng tôi không thể liên lạc đầy đủ với họ”. và Chi nhánh Cứu hộ.

After a commission examined and revamped communications procedures, the statewide response ‘has become far more professional and responsive,’ he says. There is a sense among both government officials and residents that the speed, dedication, and coordination of firefighters from several states and jurisdictions are resulting in greater efficiency than in past ‘siege fire’ situations.

Sau khi một ủy ban kiểm tra và sửa đổi các thủ tục liên lạc, công tác phản hồi trên toàn tiểu bang 'đã trở nên chuyên nghiệp và nhanh nhạy hơn nhiều', ông nói. Cả quan chức chính phủ và người dân đều có cảm giác rằng tốc độ, sự cống hiến và sự phối hợp của lính cứu hỏa từ một số tiểu bang và khu vực pháp lý đang mang lại hiệu quả cao hơn so với các tình huống 'cháy rừng bao vây' trong quá khứ.

In recent years, the Southern California region has improved building codes, evacuation procedures, and procurement of new technology. ‘I am extraordinarily impressed by the improvements we have witnessed,’ says Randy Jacobs, a Southern California- based lawyer who has had to evacuate both his home and business to escape wildfires. ‘Notwithstanding all the damage that will continue to be caused by wildfires, we will no longer suffer the loss of life endured in the past because of the fire prevention and firefighting measures that have been put in place,’ he says.

Trong những năm gần đây, khu vực Nam California đã cải thiện quy tắc xây dựng, quy trình sơ tán và sự thu mua công nghệ mới. Randy Jacobs, một luật sư ở Nam California, người đã phải sơ tán cả nhà và cơ sở kinh doanh của mình để thoát khỏi đám cháy rừng, cho biết: “Tôi vô cùng ấn tượng trước những cải tiến mà chúng tôi đã chứng kiến. Ông nói: “Bất chấp tất cả những thiệt hại sẽ tiếp tục bị gây nên bởi cháy rừng, chúng tôi sẽ không còn phải gánh chịu những thiệt hại về người như trong quá khứ nhờ có các biện pháp phòng cháy và chữa cháy đã và đang được áp dụng”.

C10 T4 P2 Second nature

Your personality isn’t necessarily set in stone. With a little experimentation, people can reshape their temperaments and inject passion, optimism, joy and courage into their lives

Tính cách của bạn không nhất thiết phải cố định. Với một chút thử nghiệm, mọi người có thể định hình lại tính khí của mình và đưa niềm đam mê, sự lạc quan, niềm vui và lòng dũng cảm vào cuộc sống của họ

Psychologists have long held that a person’s character cannot undergo a transformation in any meaningful way and that the key traits of personality are determined at a very young age. However, researchers have begun looking more closely at ways we can change. Positive psychologists have identified 24 qualities we admire, such as loyalty and kindness, and are studying them to find out why they come so naturally to some people. What they’re discovering is that many of these qualities amount to habitual behaviour that determines the way we respond to the world. The good news is that all this can be learned.

Các nhà tâm lý học từ lâu đã cho rằng tính cách của một người không thể trải qua quá trình biến đổi theo bất kỳ cách có ý nghĩa nào và các đặc điểm chính của tính cách được xác định từ khi còn rất nhỏ. Tuy nhiên, các nhà nghiên cứu đã bắt đầu xem xét kỹ hơn những cách chúng ta có thể thay đổi. Các nhà tâm lý học tích cực đã xác định được 24 phẩm chất mà chúng ta ngưỡng mộ, chẳng hạn như lòng trung thành và lòng tốt, đồng thời đang nghiên cứu chúng để tìm ra lý do tại sao chúng lại tự nhiên xuất hiện trong một số người. Những gì họ đang khám phá ra là nhiều phẩm chất trong số này tương đương với những hành vi theo thói quen có vai trò quyết định cách chúng ta phản ứng với thế giới. Tin tốt là tất cả những điều này đều có thể học được.

Some qualities are less challenging to develop than others, optimism being one of them. However, developing qualities requires mastering a range of skills which are diverse and sometimes surprising. For example, to bring more joy and passion into your life, you must be open to experiencing negative emotions. Cultivating such qualities will help you realise your full potential.

Một số phẩm chất khó phát triển hơn những phẩm chất khác, sự lạc quan là một trong số đó. Tuy nhiên, việc phát triển các phẩm chất đòi hỏi phải thành thạo một loạt các kỹ năng đa dạng và đôi khi gây ngạc nhiên. Ví dụ, để mang lại nhiều niềm vui và đam mê hơn trong cuộc sống của bạn, bạn phải cởi mở để trải nghiệm những cảm xúc tiêu cực. Trau dồi những phẩm chất như vậy sẽ giúp bạn phát huy hết tiềm năng của mình.

‘The evidence is good that most personality traits can be altered,’ says Christopher Peterson, professor of psychology at the University of Michigan, who cites himself as an example. Inherently introverted, he realised early on that as an academic, his reticence would prove disastrous in the lecture hall. So he learned to be more outgoing and to entertain his classes. ‘Now my extroverted behaviour is spontaneous,’ he says.

Christopher Peterson, giáo sư tâm lý học tại Đại học Michigan, người đã tự lấy mình làm ví dụ, cho biết: “Bằng chứng rõ ràng là hầu hết các đặc điểm tính cách đều có thể thay đổi được. Vốn là người hướng nội, anh sớm nhận ra rằng với tư cách là một học giả, tính trầm lặng của anh sẽ trở thành thảm họa trên giảng đường. Vì vậy, anh ấy đã học cách trở nên cởi mở hơn và giải trí cho các lớp học của mình. "Bây giờ hành vi hướng ngoại của tôi là tự phát," anh nói.

David Fajgenbaum had to make a similar transition. He was preparing for university, when he had an accident that put an end to his sports career. On campus, he quickly found that beyond ordinary counselling, the university had no services for students who were undergoing physical rehabilitation and suffering from depression like him. He therefore launched a support group to help others in similar situations. He took action despite his own pain – a typical response of an optimist.

David Fajgenbaum đã phải thực hiện một quá trình chuyển đổi tương tự. Anh ấy đang chuẩn bị vào đại học thì gặp một tai nạn khiến sự nghiệp thể thao của anh ấy phải chấm dứt. Trong khuôn viên trường, anh nhanh chóng nhận ra rằng ngoài tư vấn thông thường, trường đại học không có dịch vụ nào dành cho những sinh viên đang phục hồi thể chất và bị trầm cảm như anh. Do đó, anh ấy đã thành lập một nhóm hỗ trợ để giúp đỡ những người khác trong những tình huống tương tự. Anh ấy đã hành động bất chấp nỗi đau của chính mình – một phản ứng điển hình của một người lạc quan.

Suzanne Segerstrom, professor of psychology at the University of Kentucky, believes that the key to increasing optimism is through cultivating optimistic behaviour, rather than positive thinking. She recommends you train yourself to pay attention to good fortune by writing down three positive things that come about each day. This will help you convince yourself that favourable outcomes actually happen all the time, making it easier to begin taking action.

Suzanne Segerstrom, giáo sư tâm lý học tại Đại học Kentucky, tin rằng chìa khóa để gia tăng sự lạc quan là nuôi dưỡng hành vi lạc quan, thay vì suy nghĩ tích cực. Cô ấy khuyên bạn nên rèn luyện bản thân để chú ý đến vận may bằng cách viết ra ba điều tích cực xảy ra mỗi ngày. Điều này sẽ giúp bạn thuyết phục bản thân rằng những kết quả thuận lợi thực sự luôn xảy ra, giúp bạn bắt đầu hành động dễ dàng hơn.

You can recognise a person who is passionate about a pursuit by the way they are so strongly involved in it. Tanya Streeter’s passion is freediving – the sport of plunging deep into the water without tanks or other breathing equipment. Beginning in 1998, she set nine world records and can hold her breath for six minutes. The physical stamina required for this sport is intense but the psychological demands are even more overwhelming. Streeter learned to untangle her fears from her judgment of what her body and mind could do. ‘In my career as a competitive freediver, there was a limit to what I could do – but it wasn’t anywhere near what I thought it was/ she says.

Bạn có thể nhận ra một người đam mê theo đuổi một mục tiêu nào đó bằng cách họ tích cực tham gia vào đó. Niềm đam mê của Tanya Streeter là lặn tự do – môn thể thao yêu cầu lặn sâu xuống nước mà không cần bình hoặc các thiết bị thở khác. Bắt đầu từ năm 1998, cô đã lập chín kỷ lục thế giới và có thể nín thở trong sáu phút. Thể lực đòi hỏi cho môn thể thao này rất cao nhưng yêu cầu về tâm lý thậm chí còn áp đảo hơn. Streeter đã học cách giải tỏa nỗi sợ hãi của cô ấy từ sự phán đoán của cô về những gì cơ thể và tâm trí của cô ấy có thể làm. 'Trong sự nghiệp của tôi với tư cách là một vận động viên tự do cạnh tranh, có một giới hạn đối với những gì tôi có thể làm - nhưng nó không đâu gần với những gì tôi nghĩ / cô ấy nói.

Finding a pursuit that excites you can improve anyone’s life. The secret about consuming passions, though, according to psychologist Paul Silvia of the University of North Carolina, is that ‘they require discipline, hard work and ability, which is why they are so rewarding.’ Psychologist Todd Kashdan has this advice for those people taking up a new passion: ‘As a newcomer, you also have to tolerate and laugh at your own ignorance. You must be willing to accept the negative feelings that come your way,’ he says.

Tìm kiếm một mục tiêu khiến bạn phấn khích có thể cải thiện cuộc sống của bất kỳ ai. Tuy nhiên, theo nhà tâm lý học Paul Silvia của Đại học Bắc Carolina, bí mật về những đam mê cháy bỏng là 'chúng đòi hỏi kỷ luật, sự chăm chỉ và khả năng, đó là lý do tại sao chúng rất ý nghĩa'. Nhà tâm lý học Todd Kashdan có lời khuyên dành cho những người theo đuổi đam mê mới: 'Là một người mới, bạn cũng phải chịu đựng và cười nhạo sự thiếu hiểu biết của chính mình. Bạn phải sẵn sàng chấp nhận những cảm xúc tiêu cực đến với mình', ông nói.

In 2004, physician-scientist Mauro Zappaterra began his PhD research at Harvard Medical School. Unfortunately, he was miserable as his research wasn’t compatible with his curiosity about healing. He finally took a break and during eight months in Santa Fe, Zappaterra learned about alternative healing techniques not taught at Harvard. When he got back, he switched labs to study how cerebrospinal fluid nourishes the developing nervous system. He also vowed to look for the joy in everything, including failure, as this could help him learn about his research and himself.

Năm 2004, bác sĩ-nhà khoa học Mauro Zappaterra bắt đầu nghiên cứu tiến sĩ tại Trường Y Harvard. Thật không may, anh ấy rất đau khổ vì nghiên cứu của anh ấy không tương thích với sự tò mò của anh ấy về việc chữa bệnh. Cuối cùng, anh ấy đã nghỉ ngơi và trong tám tháng ở Santa Fe, Zappaterra đã học về các kỹ thuật trị liệu thay thế không được dạy ở Harvard. Khi trở lại, anh ấy chuyển phòng thí nghiệm để nghiên cứu cách dịch não tủy nuôi dưỡng hệ thần kinh đang phát triển. Anh ấy cũng thề sẽ tìm kiếm niềm vui trong mọi thứ, kể cả thất bại, vì điều này có thể giúp anh ấy hiểu thêm về nghiên cứu của mình và bản thân.

One thing that can hold joy back is a person’s concentration on avoiding failure rather than their looking forward to doing something well. ‘Focusing on being safe might get in the way of your reaching your goals,’ explains Kashdan. For example, are you hoping to get through a business lunch without embarrassing yourself, or are you thinking about how fascinating the conversation might be?

Một điều có thể kìm hãm niềm vui là sự tập trung của một người vào việc tránh thất bại hơn là mong muốn làm tốt điều gì đó. Kashdan giải thích: “Tập trung vào sự an toàn có thể cản trở bạn đạt được mục tiêu của mình. Ví dụ, là bạn đang hy vọng vượt qua bữa trưa bàn công việc mà không làm bản thân xấu hổ, hay bạn đang nghĩ xem cuộc trò chuyện có thể hấp dẫn đến mức nào?

Usually, we think of courage in physical terms but ordinary life demands something else. For marketing executive Kenneth Pedeleose, it meant speaking out against something he thought was ethically wrong. The new manager was intimidating staff so Pedeleose carefully recorded each instance of bullying and eventually took the evidence to a senior director, knowing his own job security would be threatened. Eventually the manager was the one to go. According to Cynthia Pury, a psychologist at Clemson University, Pedeleose’s story proves the point that courage is not motivated by fearlessness, but by moral obligation. Pury also believes that people can acquire courage. Many of her students said that faced with a risky situation, they first tried to calm themselves down, then looked for a way to mitigate the danger, just as Pedeleose did by documenting his allegations.

Thông thường, chúng ta nghĩ về lòng dũng cảm trên khía cạnh thể chất nhưng cuộc sống bình thường đòi hỏi một thứ khác. Đối với giám đốc tiếp thị Kenneth Pedeleose, điều đó có nghĩa là lên tiếng chống lại điều gì đó mà ông cho là sai trái về mặt đạo đức. Người quản lý mới đang đe dọa nhân viên, vì vậy Pedeleose đã cẩn thận ghi lại từng trường hợp bắt nạt và cuối cùng đưa bằng chứng cho một giám đốc cấp cao, biết rằng sự an toàn trong công việc của chính anh ta sẽ bị đe dọa. Cuối cùng, người quản lý là người ra đi. Theo Cynthia Pury, một nhà tâm lý học tại Đại học Clemson, câu chuyện của Pedeleose chứng minh rằng lòng can đảm không được thúc đẩy bởi sự dũng cảm, mà bởi nghĩa vụ đạo đức. Pury cũng tin rằng mọi người có thể có được lòng dũng cảm. Nhiều học sinh của cô nói rằng khi đối mặt với một tình huống rủi ro, đầu tiên họ cố gắng trấn tĩnh bản thân, sau đó tìm cách giảm thiểu nguy hiểm, giống như Pedeleose đã làm bằng cách ghi lại những cáo buộc của mình.

Over the long term, picking up a new character trait may help you move toward being the person you want to be. And in the short term, the effort itself could be surprisingly rewarding, a kind of internal adventure.

Về lâu dài, việc phát triển một đặc điểm tính cách mới có thể giúp bạn tiến tới việc trở thành người mà bạn muốn trở thành. Và trong ngắn hạn, bản thân nỗ lực đó có thể mang lại kết quả đáng ngạc nhiên, như một cuộc phiêu lưu tâm lý.

C10 T4 P3 When evolution runs backwards

Evolution isn’t supposed to run backwards – yet an increasing number of examples show that it does and that it can sometimes represent the future of a species.

Tuy nhiên, tiến hoá không được cho là sẽ chạy ngược lại - ngày càng có nhiều ví dụ cho thấy rằng điều đó thực sự xảy ra và đôi khi nó còn có thể đại diện cho tương lai của một loài.

The description of any animal as an ‘evolutionary throwback’ is controversial. For the better part of a century, most biologists have been reluctant to use those words, mindful of a principle of evolution that says ‘evolution cannot run backwards. But as more and more examples come to light and modern genetics enters the scene, that principle is having to be rewritten. Not only are evolutionary throwbacks possible, they sometimes play an important role in the forward march of evolution.

Việc mô tả bất kỳ loài động vật nào như là một ‘sự quay lại đặc điểm tổ tiên’ vẫn còn gây tranh cãi. Trong phần lớn thế kỷ qua, hầu hết các nhà sinh học đã ngần ngại sử dụng cụm từ đó, vì họ luôn ghi nhớ một nguyên lý của tiến hóa cho rằng ‘tiến hóa không thể chạy ngược lại’. Tuy nhiên, khi ngày càng nhiều ví dụ được phát hiện và di truyền học hiện đại tham gia vào lĩnh vực này, nguyên lý đó đang buộc phải được viết lại. Không chỉ những trường hợp quay lại đặc điểm tổ tiên là có thể xảy ra, mà đôi khi chúng còn đóng vai trò quan trọng trong bước tiến của tiến hóa.

The technical term for an evolutionary throwback is an ‘atavism’, from the Latin atavus, meaning forefather. The word has ugly connotations thanks largely to Cesare Lombroso, a 19th-century Italian medic who argued that criminals were born not made and could be identified by certain physical features that were throwbacks to a primitive, sub-human state.

Thuật ngữ chuyên môn dùng để chỉ hiện tượng quay lại đặc điểm tổ tiên là ‘atavism’, bắt nguồn từ tiếng Latin atavus, có nghĩa là ‘tổ tiên’. Từ này mang những hàm ý tiêu cực, phần lớn là do Cesare Lombroso, một nhà y học người Ý thế kỷ 19, người đã lập luận rằng tội phạm sinh ra đã là tội phạm chứ không phải do xã hội tạo nên, và rằng họ có thể được nhận diện qua một số đặc điểm hình thể được xem là sự quay lại trạng thái nguyên thủy, dưới mức con người.

While Lombroso was measuring criminals, a Belgian palaeontologist called Louis Dollo was studying fossil records and coming to the opposite conclusion. In 1890 he proposed that evolution was irreversible: that ‘an organism is unable to return, even partially, to a previous stage already realised in the ranks of its ancestors. Early 20th-century biologists came to a similar conclusion, though they qualified it in terms of probability, stating that there is no reason why evolution cannot run backwards -it is just very unlikely. And so the idea of irreversibility in evolution stuck and came to be known as ‘Dollo’s law.

Trong khi Lombroso đang nghiên cứu các tội phạm, một nhà cổ sinh vật học người Bỉ tên là Louis Dollo lại đang nghiên cứu các tư liệu hóa thạch và đi đến một kết luận trái ngược. Năm 1890, ông đề xuất rằng tiến hóa là không thể đảo ngược: ‘một sinh vật không thể quay trở lại, dù chỉ một phần, về một giai đoạn trước đó đã từng tồn tại trong các thế hệ tổ tiên của nó.’ Các nhà sinh học đầu thế kỷ 20 cũng đi đến kết luận tương tự, tuy nhiên họ bổ sung rằng điều này cần được hiểu theo nghĩa xác suất, cho rằng không có lý do gì khiến tiến hóa không thể quay ngược lại – chỉ là điều đó rất khó xảy ra. Vì vậy, quan điểm về tính không thể đảo ngược của tiến hóa được duy trì và dần được biết đến với tên gọi ‘Định luật Dollo’.

If Dollo’s law is right, atavisms should occur only very rarely, if at all. Yet almost since the idea took root, exceptions have been cropping up. In 1919, for example, a humpback whale with a pair of leg - like appendages over a metre long, complete with a full set of limb bones, was caught off Vancouver Island in Canada. Explorer Roy Chapman Andrews argued at the time that the whale must be a throwback to a land-living ancestor. ‘I can see no other explanation,’ he wrote in 1921.

Nếu định luật Dollo là đúng, thì các trường hợp atavism lẽ ra chỉ xảy ra rất hiếm, nếu có xảy ra đi nữa. Tuy nhiên, gần như ngay từ khi quan điểm đó bén rễ, các trường hợp ngoại lệ đã liên tục xuất hiện. Ví dụ, vào năm 1919, một con cá voi lưng gù với một cặp chi phụ giống chân dài hơn một mét, hoàn chỉnh với đầy đủ các xương chi, đã bị bắt được ngoài khơi đảo Vancouver ở Canada. Nhà thám hiểm Roy Chapman Andrews khi đó cho rằng con cá voi này hẳn là một trường hợp quay lại đặc điểm của tổ tiên sống trên cạn. “Tôi không thấy lời giải thích nào khác,” ông viết vào năm 1921.

Since then, so many other examples have been discovered that it no longer makes sense to say that evolution is as good as irreversible. And this poses a puzzle: how can characteristics that disappeared millions of years ago suddenly reappear? In 1994, Rudolf Raff and colleagues at Indiana University in the USA decided to use genetics to put a number on the probability of evolution going into reverse. They reasoned that while some evolutionary changes involve the loss of genes and are therefore irreversible, others may be the result of genes being switched off. If these silent genes are somehow switched back on, they argued, long-lost traits could reappear.

Kể từ đó, rất nhiều ví dụ khác đã được phát hiện, đến mức việc nói rằng tiến hóa gần như không thể đảo ngược không còn hợp lý nữa. Và điều này đặt ra một câu hỏi khó: làm thế nào mà những đặc điểm đã biến mất từ hàng triệu năm trước lại có thể đột nhiên xuất hiện trở lại? Vào năm 1994, Rudolf Raff và các đồng nghiệp tại Đại học Indiana ở Hoa Kỳ đã quyết định sử dụng di truyền học để định lượng xác suất của việc tiến hóa diễn ra theo chiều ngược lại. Họ lập luận rằng trong khi một số thay đổi tiến hóa liên quan đến việc mất đi các gen và vì vậy không thể đảo ngược, thì những thay đổi khác có thể chỉ là kết quả của việc các gen bị ‘tắt’. Họ cho rằng nếu những gen ‘im lặng’ này bằng cách nào đó được bật trở lại, thì những đặc điểm đã mất từ lâu có thể xuất hiện trở lại.

Raff’s team went on to calculate the likelihood of it happening. Silent genes accumulate random mutations, they reasoned, eventually rendering them useless. So how long can a gene survive in a species if it is no longer used? The team calculated that there is a good chance of silent genes surviving for up to 6 million years in at least a few individuals in a population, and that some might survive as long as 10 million years. In other words, throwbacks are possible, but only to the relatively recent evolutionary past.

Nhóm nghiên cứu của Raff sau đó tiếp tục tính toán xác suất của việc này xảy ra. Họ lập luận rằng các gen ‘im lặng’ sẽ tích lũy các đột biến ngẫu nhiên, và theo thời gian điều này sẽ khiến chúng trở nên vô dụng. Vậy một gen có thể tồn tại trong một loài bao lâu nếu nó không còn được sử dụng nữa? Nhóm nghiên cứu tính toán rằng có khả năng khá cao các gen ‘im lặng’ có thể tồn tại tới khoảng 6 triệu năm ở ít nhất một vài cá thể trong một quần thể, và một số thậm chí có thể tồn tại tới 10 triệu năm. Nói cách khác, những trường hợp quay lại đặc điểm tổ tiên là có thể xảy ra, nhưng chỉ đối với quá khứ tiến hóa tương đối gần.

As a possible example, the team pointed to the mole salamanders of Mexico and California. Like most amphibians these begin life in a juvenile ‘tadpole’ state, then metamorphose into the adult form – except for one species, the axolotl, which famously lives its entire life as a juvenile. The simplest explanation for this is that the axolotl lineage alone lost the ability to metamorphose, while others retained it. From a detailed analysis of the salamanders’ family tree, however, it is clear that the other lineages evolved from an ancestor that itself had lost the ability to metamorphose. In other words, metamorphosis in mole salamanders is an atavism. The salamander example fits with Raff’s 10million-year time frame.

Như một ví dụ có thể, nhóm nghiên cứu đã chỉ ra các loài kỳ giông mole ở Mexico và California. Giống như hầu hết các loài lưỡng cư, chúng bắt đầu cuộc sống ở dạng ấu trùng (nòng nọc), sau đó biến thái thành dạng trưởng thành – ngoại trừ một loài là axolotl, loài nổi tiếng vì sống suốt cuộc đời ở dạng ấu trùng. Lời giải thích đơn giản nhất cho hiện tượng này là chỉ riêng dòng tiến hóa của axolotl đã mất khả năng biến thái, trong khi các loài khác vẫn giữ khả năng đó. Tuy nhiên, từ một phân tích chi tiết về cây phả hệ của các loài kỳ giông, rõ ràng rằng các dòng tiến hóa khác đã tiến hóa từ một tổ tiên mà bản thân nó cũng đã mất khả năng biến thái. Nói cách khác, sự biến thái ở các loài kỳ giông mole là một dạng atavism. Ví dụ về kỳ giông phù hợp với khung thời gian 10 triệu năm mà Raff đưa ra.

More recently, however, examples have been reported that break the time limit, suggesting that silent genes may not be the whole story. In a paper published last year, biologist Gunter Wagner of Yale University reported some work on the evolutionary history of a group of South American lizards called Bachia. Many of these have minuscule limbs; some look more like snakes than lizards and a few have completely lost the toes on their hind limbs. Other species, however, sport up to four toes on their hind legs. The simplest explanation is that the toed lineages never lost their toes, but Wagner begs to differ. According to his analysis of the Bachia family tree, the toed species re-evolved toes from toeless ancestors and, what is more, digit loss and gain has occurred on more than one occasion over tens of millions of years.

So what’s going on? One possibility is that these traits are lost and then simply reappear, in much the same way that similar structures can independently arise in unrelated species, such as the dorsal fins of sharks and killer whales. Another more intriguing possibility is that the genetic information needed to make toes somehow survived for tens or perhaps hundreds of millions of years in the lizards and was reactivated. These atavistic traits provided an advantage and spread through the population, effectively reversing evolution.

But if silent genes degrade within 6 to million years, how can long-lost traits be reactivated over longer timescales? The answer may lie in the womb. Early embryos of many species develop ancestral features. Snake embryos, for example, sprout hind limb buds. Later in development these features disappear thanks to developmental programs that say ‘lose the leg’. If for any reason this does not happen, the ancestral feature may not disappear, leading to an atavism.