Captain Cook Arrow Legend(库克船长弓箭的传说)
It was a great legend while it lasted, but DNA testing has finally ended a two-century-old story of the Hawaiian arrow carved from the bone of British explorer Captain James Cook who died in the Sandwich Islands in 1779.
―There is no Cook in the Australian Museum,‖ museum collection manager Jude Philip said not long ago in announcing the DNA evidence that the arrow was not made of Cook’s bone. But that will not stop the museum from continuing to display the arrow in its exhibition, ―Uncovered: Treasures of the Australian Museum,‖ which does include a feather cape presented to Cook by Hawaiian King Kalani’opu’u in 1778.
Cook was one of Britain’s great explorers and is credited with discovering the ―Great South Land,‖ now Australia, in 1770. He was clubbed to death in the Sandwich Islands, now Hawaii.
The legend of Cook’s arrow began in 1824 when Hawaiian King Kamehameha on his deathbed gave the arrow to William Adams, a London surgeon and relative of Cook’s wife, saying it was made of Cook’s bone after the fatal fight with islanders.
In the 1890s the arrow was given to the Australian Museum and the legend continued until it came face-to-face with science.
DNA testing by laboratories in Australia and New Zealand revealed the arrow was not made of Cook’s bone but was more likely made of animal bone, said Philp.
However, Cook’s fans refuse to give up hope that one Cook legend will prove true and that part of his remains will still be uncovered, as they say there is evidence not all of Cook’s body was buried at sea in 1779. ―On this occasion technology has won,‖ said Cliff Thornton,president of the Captain Cook Society, in a statement from Britain. ―But I am sure that one of these days …one of the Cook legends will prove to be tr ue and it will happen one day.‖
Avalanche and Its Safety(雪崩和安全问题)
An avalanche is a sudden and rapid flow of snow, often mixed with air and water, down a mountainside. Avalanches are among the biggest dangers in the mountains for both life and property.
All avalanches are caused by an over-burden of material, typically snowpack, that is too massive and
Terrain slopes flatter than 25 degrees or steeper than 60 degrees typically have a low risk of avalanche. Snow does not gather significantly on steep slopes; also, snow does not flow easily on flat slopes. Human-triggered avalanches have the greatest incidence when the snow’s angle of rest is between 35 and 45 degrees; the critical angle, the angle at which the human incidence of avalanches is greatest, is 38 degrees. The rule of thumb is : A slope that is flat enough to hold snow but steep enough to ski has the potential to generate an avalanche, regardless of the angle. Additionally, avalanche risk increases with use; that is , the more a slope is disturbed by skiers, thd more likely it is that an avalanche will occur.
Due to the complexity of the subject, winter travelling in the backcountry is never 100% safe. Good avalanche safety is a continuous process, including route selection and examination of the snowpack, weather conditions, and human factors. Several well-known good habits can also reduce the risk. If local authorities issue avalanche risk reports, they should be considered and all warnings should be paid attention to. Never follow in the tracks of others without your own evaluations; snow conditions are almost certain to have changed since they were made. Observe the terrain and note obvious avalanche paths where plants are missing or damaged. Avoid traveling below others who might trigger an avalanche.
What Is the Coolest Gas in the Universe?(宇宙中哪种气体温度最低?)
What is the coldest air temperature ever recorded on the Earth? Where was this low temperature recorded? The coldest recorded temperature on Earth was -91℃, which occurred in Antarctica in 1983.
We encounter an interesting situation when we discuss temperatures in space. Temperatures in Earth orbit actually range from about +120℃to -120℃. The temperature depends upon whether you are in direct sunlight or shade. Obviously, -120℃ is colder than our body can safely endure. Thank NASA science for well-designed space suits that protect astronauts from these temperature extremes.
The space temperatures just discussed affect only our area os the solar system . Obviously, it is hotter closer to the Sun and colder as we travel away from the Sun. Astronomers estimate temperatures at Pluto are about -210℃. How cold is the lowest estimated temperature in the entire universe? Again, it depends upon your location. We are taught it is supposedly impossible to have a temperature below absolute zero, which is -273℃, at which atoms do not move. Two scientists, whose names are Cornell and Wieman, have successfully cooled down a gas to a temperature barely above absolute zero. They won a Nobel Prize in Physics in 2001 for their
In the 1920s, Satyendra Nath Bose was studying an interesting theory about special light particles we now call photons. Bose had trouble convincing other scientists to believe his theory, So he contacted Albert Einstein. Einstein’s calculations help ed him theorize that atoms would behave as Bose thought—but only at very cold temperatures.
Scientists have also discovered that ultra-cold atoms can help them make the world’s atomic clocks even more accurate. These clocks are so accurate today they would only lose one second every six million years! Such accuracy will help us travel in space because distance is velocity times time(d=v*t). With the long distances involved in space travel, we need to know time as accurately as possible to get accurate distance.
Animal’s “Sixth Sense”(动物的”第六感”)
A tsunami was triggered by an earthquake in the Indian Ocean in December, 2004. It killed tens of thousands of people in Asia and East Africa. Wild animals, however, seem to have escaped that terrible tsunami. This ph enomenon adds weight to notions that they possess a ―sixth sense‖ for disasters, experts said.
Sri Lankan wildlife officials have said the giant waves that killed over 24000 people along the Indian Ocean island’s coast clearly missed wild beasts, with no dead animals found.
―No elephants are dead, not even a dead rabbit. I think animals can sense disaster. They have a sixth sense. They know when things are happening,‖ H.D. Ratnayake, deputy director of Sri Lanka’s Wildlife Department, said about one month after the tsunami attack. The waves washed floodwaters up to 2 miles inland at Yala National Park in the ravaged southeast, Sri Lanka’s biggest wildlife reserve and home to hundreds of wild elephants and several leopards.
―There has been a lot of apparent evidence about dogs barking or birds migrating before volcanic eruptions or earthquakes. But it has not been proven,‖ said Matthew van lierop, an animal behavior specialist at Johannesburg Zoo.
―There have been no specific studies because you can’t really test it in a lab or field setting,‖ he told Reuters. Other authorities concurred with this assessment.
―Wildlife seem to be able to pick up certain phenomenon, especially birds… there are many reports of birds detecting impending disasters,‖ said Clive Walk er, who has written several books on African wildlife.
Animals certainly rely on the known senses such as smell or hearing to avoid danger such as predators.
The notion of an animal ―sixth sense‖ –or some other mythical power –is an enduring one which the evidence on Sri Lanka’s ravaged coast is likely to add to.
The Romans saw owls as omens of impending disaster and many ancient cultures viewed elephants as sacred animals endowed with special powers or attributes.
A company in Leeds could change all that with directional sound alarms capalbe of guiding you to the exit.
Sound Alert, a company run by the University of Leeds, is installing the alarms in a residential home for blind people in Sommerset and a resource centre for the blind in Cumbria. The alarms produce a wide range of frequencies that enable the brain to determine where the sound is coming from.
Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be heard by humans. ―It is a burst of white n oise that people say sounds like static on the radio,‖ she says. ―Its life-saving potential is great.‖
She conducted an experiment in which people were filmed by thermal-imaging cameras trying to find their way out of a large smoke-filled room. It took them nearly four minutes to find the door without a sound alarm, but only 15 seconds with one.
Withington studies how the brain processes sounds at the university. She says that the source of a wide band of frequencies can be pinpointed more easily than the source of a narrow band. Alarms based on the same concept have already been installed on emergency vehicles.
The alarms will also include rising or falling frequencies to indicate whether people should go up or down stairs. They were developed with the aid of a large grant from British Nuclear Fuels.
Car Thieves Could Be Stopped Remotely(远程制止偷车贼)
Speeding off in a stolen car, the thief thinks he has got a great catch. But he is in a nasty surprise. The car is fitted with a remote immobilizer, and a radio signal from a control center miles away will ensure that once the thief switches the engine off, he will not be able to start it again.
For now, such devices are only available for fleets of trucks and specialist vehicles used on construction sites. But remote immobilization technology could soon start to trickle down to ordinary cars, and should be available to ordinary cars in the UK in two months.
The idea goes like this. A control box fitted to the car incorporates a miniature cellphone, a microprocessor and memory, and a GPS satellite positioning receiver. If the car is stolen, a coded cellphone signal will tell the unit to block the vehicle’s engine management system and prevent the engine being restarted.
There are even plans for immobilizers that shut down vehicles on the move, though there are fears over the safety implications of such a system.
In the UK, an array of technical fixes is already making life harder for car thieves. ―The pattern of vehicles crime has changed,‖ says Martyn Rand all of Thatcham, a security research organization based in Berkshire that is funded in part by the motor insurance industry.
He says it would only take him a few minutes to teach a novice how to steal a car, using a bare minimum of tools. But only if the car is more than 10 years old.
Modern cars are a far tougher proposition, as their engine management computer will not allow them to start unless they receive a unique ID code beamed out by the ignition key. In the UK, technologies like this have helped achieve a 31 per cent drop in vehicle-related crime since 1997.
But determined criminals are still managing to find other ways to steal cars. Often by getting hold of the owner’s keys in a burglary. In 2000, 12 per cent of vehicles stolen in the UK were taken by using the owner’s keys, which doubles the previous year’s figure.
Remote-controlled immobilization system would put a major new obstacle in the criminal’s way by making such thefts pointless. A group that includes Thatcham, the police, insurance companies and security technology firms have developed standards for a system that could go on the market sooner than the
An Intelligent Car(智能汽车)
Driving needs sharp eyes, keen ears, quick brain, and coordination between hands and the brain. Many human drivers have all these and can control a fast-moving car. But how does an intelligent car control itself?
There is a virtual driver in the smart car. This virtual driver has ―eyes‖, ―brains‖, ―hands‖ and ―feet‖, too. The minicameras on each side of the car are his ―eyes‖, w hich observe the road conditions ahead of it. They watch the traffic to the car’s left and right. There is also a highly automatic driving system in the car. It is the built-in computer, which is the virtual driver’s―brain‖. His ―brain‖ calculates the spe eds of other moving cars near it and analyzes their positions. Basing on this information, it chooses the right path for the intelligent car, and gives instructions to the ―hands‖and ―feet‖ to act accordingly. In this way, the virtual driver controls his car.
What is the virtual driver’s best advantage? He reacts quickly. The minicameras are sending images continuously to the ―brain.‖ It completes the processing of the images within 100 milliseconds. However, the world’s best driver at least needs one second to react. Besides, when he takes action, he needs one more second.
The virtual driver is really wonderful. He can reduce the accident rate considerably on expressways. In this case, can we let him have the wheel at any time and in amy place? Experts warn that we cannot do that just yet.
A Biological Clock(生物钟)
Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells plants when to form flowers and when the flowers should open. It tells insects when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal affect the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur because of the number of hours of daylight. In the short days of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer.
Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration flight twice each year. Birds prevented from flying become restless when it is time for the trip, but they become calm again when the time of the flight has ended.
Scientists say they are beginning to learn which parts of the brain contain biological clocks. An American
Scientists say there probably are other biological clock cells that control other body activities.
Dr. Moorhead is studying how our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours.
It can take many days for a human body to accept the major change in work hours. Dr. Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said such understanding could cut sickness and accidents at work and would help increase a factory’s production.
Spider webs are more than homes, and they are ingenious traps. And the world’s best web spinner may be the Golden Orb Weaver spider. The female Orb Weaver spins a web of fibers thin enough to be invisible to insect prey, yet tough enough to snare a flying bird without breaking.
The secret of the web’s strength? A type of super-resilient silk called dragline. When the female spider is ready to weave the web’s spokes and frame, she uses her legs to draw the airy thread out through a hollow nozzle in her belly. Dragline is not sticky, so the spider can race back and forth along it to spin the web’s trademark spiral.
Unlike some spiders that weave a new web every day, a Golden Orb Weaver reuses her handiwork until it falls apart, sometimes not for two years. The silky thread is five times stronger than steel by weight and absorbs the force of an impact three times better than Kevlar, a high-strength human-made material used in bullet-proof vests. And thanks to its high tensile strength, or the ability to resist breaking under the pulling force called tension, a single strand can stretch up to 40 percent longer than its original length and snap back as well as new. No human-made fiber even comes close.
It is no wonder manufacturers are clamoring for spider silk. In the consumer pipeline: high-performance fabrics for athletes and stockings that never run. Think parachute cords and suspension bridge cables. A steady supply of spider silk would be worth billions of dollars –but how to produce it? Harvesting silk on spider farms does not work because the territorial arthropods have a tendency to devour their neighbors.
Now, scientists at the biotechnology company Nexia are spinning artificial silk modeled after Golden Orb dragline. The first step: extract silk-making genes from the spiders. Next, implant the genes into goat egg cells.
the spinning process, but they hope artificial spider silk will soon be snagging customers as fast as the real thing snags bugs.
Less Is More（更少是更多）
It sounds all wrong – drilling holes in a piece of wood to make it more resistant to knocks. But it works because the energy from the blow gets distributed throughout the wood rather than focusing on one weak spot. The discovery should lead to more effective and lighter packaging materials.
Carpenters have known for centuries that some woods are tougher than others. Hickory, for example, was turned into axe handles and cartwheel spokes because it can absorb shocks without breaking. White oak, for example, is much more easily damaged, although it is almost as dense. Julian Vincent at Bathe University and his team were convinced the wood’s internal structure could explain the differences.
Many trees have tubular vessels that run up the trunk and carry water to the leaves. In oak they are large, and arranged in narrow bands, but in hickory they are smaller, and more evenly distributed. The researchers thought this layout might distribute a blow’s e nergy throughout the wood, soaking up a bigger hit. To test the idea, they drilled holes 0.65 millimetres across into a block of spruce, a wood with no vessels, and found that it withstood a harder knock. Only when there were more than about 30 holes per s quare centimetre did the wood’s performance drop off.
A uniform substance doesn’t cope well with knocks because only a small proportion of the material is actuslly affected. All the energy from the blow goes towards breakingthe material in one or two places, but often the pieces left behind are pristine.
But instead of the energy being concentrated in one place, the holes provide many weak spots that all absorb energy as they break, says Vincent. ―You are controlling the places where the wood breaks, and it can then absorb more energy, more safely.‖
The researchers believe the principlw could be applied to any material –for example, to manufacture lighter and more protective packaging. It could also be used in car bumpers, crash barriers and armour for military vehicles, says Ulrike Wegst, at the Max Plank Institute for Mental Research in Stuttgart. But she emphasizes that you’d need to design the substance with the direction of force in mind. ―The direction of loading is crucial,‖ she says.
China to Help Europe Develop GPS Rival（中国帮助欧洲发展全球定位系统的竞争）China is to contribute to a new global satellite navigation system being developed by European nations. The Galileo satellite system will offer a more accurate civilian alternative to the Global Positioning System (GPS), operated by the US military. China will provide 230m Euros (USD 259m) in funding and will cooperate with technical, manufacturing and market development. ―China will help Galileo to become the major world infrastructure for the growing market for location services,‖ said Loyola de Palacio, EU transport commissioner.
A new center that will coordinate co-operation was also announced by the European Commission, the European Space Agency (ESA) and the Chinese Ministry of Science and Technology not long ago. The China-Europe Global Navigation Satellite System Technical Training and Cooperation Center will be located at Beijing
The US has claimed that Galileo could interfere with the US ability to downgrade the GPS service during military conflicts. European officials say this is unfounded and counter that US opposition is due to the commercial challenge Galileo would present to GPS. Galileo will be precise to within a meter, while the civilian GPS service is accurate to around 10 meters.
The Galileo satellite constellation will consist of27 operational and three reserve satellites orbiting the Earth at an altitude of 23600 km. The satellites will be strung along three medium-Earth orbits at 56 degrees inclination to the equator and will provide global coverage. The system should be operational by 2008 and the entire project is expected to cost around 3.2 billion Euros (USD 3.6 billion).
The European Commission has said Galileo will primarily be used for transportation technology, scientiflc research, land management and disaster monitoring.
Galileo will provide two signals: a standard civilian one and an encrypted, wide-band signal called the Public Regulated Service (PRS). This second signal is designed to withstand localized jamming and will be used by police and military services in Europe. European Commission officials have said China will not be given access to the PRS.
The first Galileo satellite is scheduled to launch late in 2004. Clocks on board the satellite will be synchronized through 20 ground sensors stations, two command centers and 15 uplink stations.
Receivers on the ground will use time signals from the satellites to precisely calculate their location. A ―search and rescue‖ function will also let distress signals be relayed through the constellation of satellites.
University of Toronto and the University of Montreal have found that smoking may actually increase depressive symptoms in some teens.
―This observational study is one of the few to examine the perceived emotional benefits of smoking among teens,‖ says lead researcher Michael Chaiton, a research associate at the Ontario Tob acco Research Unit of the University of Toronto. ―Although cigarettes may appear to have self-medicating effects or to improve mood, in the long term we found that teens who started to smoke reported higher depressive symptoms.‖As part of the study, some 662 high school teenagers completed up to 20 questionnaires about their use of cigarettes to affect mood. Secondary schools were selected to provide a mix of French and English participants, urban and rural schools, and schools located in high, moderate and low socioeconomic neighbourhoods.
Participants were divided into three groups: never smokers; smokers who did not use cigarettes to self-medicate, improve mood or physical state; smokers who used cigarettes to self-medicate.Depressive symptoms were measured using a scale that asked how often participants felt too tired to do things; had trouble going to sleep or staying asleep; felt unhappy, sad, or depressed; felt hopeless about the future; felt vexed, antsy or tense; and worried too much about things.
―Smokers who used cigarettes as mood improvers had higher risks of elevated depressive symptoms than teens who had never smoked,‖ says co-researcher Jennifer O’Loughlin, a professor at the University of Montreal Department of Social and Preventive Medicine. ―Our study found that teen smokers who reported emotional benefits from smoking are at higher risk of developing depressive symptoms.‖The association between depression and smoking exists principally among teens that use cigarettes to feel better. ―It’s important to emphasize that depressive symptom scores were higher among teenagers who reported emotional benefits from smoking after they began to smoke,‖ says Dr. Chaiton.
C ell Phone Lets Your Secret Out（手机泄漏了你的秘密）
Your cell phone holds secrets about you. Besides the names and numbers that you've programmed into it, traces of your DNA2linger on the device, according to a new study.
DNA is genetic material that appears in every cell. Like your fingerprint, your DNA is unique to you unless you have an identical twin. Scientists today routinely analyze DNA in blood, saliva, or hair left behind at the scene of a crime. The results often help detectives identify criminals and their victims. Your cell phone can reveal more about you than you might think.
Meghan J. McFadden, a scientist at McMaster University1in Hamilton, Ontario, heard about a crime in which the suspect bled onto a cell phone and later dropped the device This made her wonder whether traces of DNA lingered on cell phones--even when no blood was involved.So she and colleague Margaret Wallace of the City University of New York analyzed the flip-open phones3 of 10 volunteers. They used swabs to collect invisible traces of the users from two parts of the phone: the outside, where the user holds it, and the speaker, which is placed at the user's ear.
The scientists scrubbed the phones using a solution made mostly of alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones back for another week. Then the researchers collected the phones and repeated the swabbing of each phone once more.
people who had apparently also handled the phone.Surprisingly, DNA showed up even in swabs that were taken immediately after the phones were scrubbed. That suggests that washing won't remove all traces of evidence from a criminal's device. So cell phones can now be added to the list of clues that can clinch a crime-scene investigation.
Sharks Perform a Service for Earth's Waters（鲨鱼有益于地球）
It is hard to get people to think of sharks as anything but a deadly enemy1. They are thought to attack people frequently. But these fish2 perform a valuable service for earth's waters and for human beings. Yet business and sport fishing3 are threatening their existence Some sharks are at risk of disappearing from Earth
Warm weather may influence both fish and shark activity. Many fish swim near coastal areas because of their warm waters. Experts say sharks may follow the fish into the same areas, where people also swim. In fact, most sharks do not purposely charge at or bite humans. They are thought to mistake a person for a sea animal, such as a seal or sea lion. That is why people should not swim in the ocean when the sun goes down or comes up. Those are the times when sharks are looking for food. Experts also say that bright colors and shiny jewelry may cause sharks to attack.
A shark has an extremely good sense of smell4' It can find small amounts of substances in water, such as blood, body liquids and chemicals produced by animals. These powerful senses help sharks fred their food. Sharks eat fish, any other sharks, and plants that live in the ocean.
Medical researchers want to learn more about the shark's body defense, and immune systems against disease. Researchers know that sharks recover quickly from injuries. They study the shark in hopes of finding a way to fight human disease.
Sharks are important for the world's oceans They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too great This protects the plants and other forms of life that exist in the oceans.
Young Adults Who Exercise Get Higher IQ Scores（运动的年轻人智商更高）
Young adults who are fit have a higher IQl and are more likely to go on to university，reveals a major new study2 carried out at the Sahlgrenska Academy3 and Sahlgrenska University Hospital．
The results were recently published in the Proceedings of the National Academy of Sciences (PNAS)4．The study involved l.2 million Swedish men doing military service who were born between l 950 and l976．The research group analysed the results of both physical and IQ tests the youngsters took fight after they started serving the army．
The study shows a clear link between good physical fitness and better results for the IQ test．The strongest links are for logical thinking and verbal comprehension．But it is only fitness that plays a role in the results for the IQ test5，and not strength．―Being fit means that you also have good heart and lung capacity and that your brain gets plenty of oxygen，‖says Michael Nilsson，professor at the S ahlgrenska Academy and chief physician at the Sahlgrenska University Hospital．―This may be one of the reasons why we can see a clear link with fitness，but not with muscular strength．We are also seeing that there are growth factors that are important．‖By analysing data for twins，the researchers have been able to determine that it is primarily environmental factors and not genes that explain the link between fitness and a higher IQ．
―We have also shown that those youngsters who improve their physical fitness between ages of l5 and l8 increase their cognitive performance," says Mafia Aberg，researcher at the Sahlgrenska Academy and physician at Aby health centre．―This being the case6，physical education is a subject that has an important place in schools，and is an absolute must7 if we want to do well in maths and other theoretical subjects.‖
The researchers have also compared the results from fitness tests during naltioal service8 with the socio-economic status of the men later in life．Those who were fit at l 8 were more likely to go into higher education，and many secured more qualified jobs．