Ebbysemeyer—King of Currents
On December 9, 1994, the Huundai Seattle, a large freighter, lost 49 containers of cargo during a storm in the middle of the Pacific Ocean. Among the cargo that fell overboard were some 34, 000 hockey gloves. Unable to retrieve the lost cargo, the ship headed for its destination in the United States.
What happened to the hockey gloves? Eight months later, the crew of a fishing boat found seven of them 1, 300 kilometers off the Oregon coast. Six months after that, the rest of the gloves began washing up on beaches in Washington state.
“Just as my colleague Jay Ingraham and I predicted,” said Ebbyesemeyer, a scientist in Seattle. An authority on ocean currents, Ebbysemeyer has been called the “King of Currents.” For more than 30 years, he has been tracking an assortment of floating objects—everything from huge icebergs to tiny bathtub toys. With his knowledge of ocean currents and sophisticated computer program developed by Ingraham, he can now predict with amazing accuracy which way floating objects will drift and where and when they will reach shore.
Why is it important to know such things? Because, Ebbysemeyer points out, knowledge of ocean currents can help determine how far an oil spill might spread or where the sewage from a treatment plant will go. By mapping currents, scientists can also figure out where plankton might drift or what paths salmon will take through the ocean to reach the streams of their birth.
Ebbysemeyer says currents are like giant rivers in the ocean. They are found both at the ocean's surface and several thousands feet down on the seafloor.
Surface currents are driven mainly by the wind and by earth's rotation, through a force called the Coriolis effect. As the wind pushes the water forward, the Coriolis effect nudges it slightly sideways. The two influences combine to make surface waters move in great loops.
Deep ocean currents are created as seawater approaches the North and South Poles. As the water cools, its molecules draw closer together, making each gallon denser. Heavier than warm water, the cold water sinks to the ocean floor, miles beneath the surface flows. The deep currents then drift toward the equator, where they are gradually heated by the sun. The water molecules spread out again, and the lighter, less dense fluid rises to the surface.
That is not the whole story, Ebbysemeyer says. Before you can accurately predict where or when a floating object will reach a particular shore, you must also consider certain details. One detail is windage. To calculate windage, Ebbysemeyer floats various items—cans, bottles, shoes—in a tank, then blasts each one with the breeze from a powerful fan.
“Some things sit on the water and just scoot right along,” said Ebbysemeyer. “Others are fairly well submerged and are not exposed to the wind much at all. A rubber bathtub toy might move at a rate of around 48 kilometers per day, compared with an athletic shoe, which will cover only 32 kilometers in the same period.”
Ebbysemeyer estimates that a thousand containers of cargo fall into the sea from ships every year. His data suggest that some of those items can remain adrift for years before washing shore. He cites the case of an unknown Nike sneaker that washed ashore in Washington after floating for three years in the Pacific Ocean. “It was still quite wearable,” said Ebbysemeyer.
1. What happened to those hockey gloves that fell overboard?
A. They were retrieved by the crew.
B. Some of them reached shore at last.
C. They sank to the seafloor.
D. They were completely lost in the vast ocean.
2. Why does Ebbysemeyer study ocean currents?
A. For pragmatic purposes.
B. For fun.
C. Just out of curiosity.
D. To study the lives of plankton.
3. All the factors that affect ocean currents are discussed in the passage EXCEPT
A. the sun's heat
B. rotation of the earth.
C. gravitational force.
4. What creates deep ocean currents?
A. High temperatures near the equator.
B. Magnetic force near the South Pole.
C. Magnetic force near the North Pole.
D. Low temperatures near the two Poles.
5. What does the example of a Nike sneaker given in the last paragraph indicate?
A. Nike products are most durable.
B. Sometimes, objects may drift in the ocean for years.
C. Seawater erodes drifting objects including Nike products.
D. The Nike sneaker is still wearable after years of drifting.
The Net Cost of Making a Name for Yourself
Companies are paying up to $10, 000 to register a domain name on the Internet even though there is no guarantee that they will get the name they want.
The task of registering domains ending in .com, .org, .edu and .net is at present contracted out by the US government to the Virginia-based company Network Solutions. The contract runs out this year, and the government wants to bring in a different scheme.
But last year, an ad hoc committee of the Internet's great and good revealed its own plan. This involved setting up seven new domains, each indicating the kind of business or organisation using that name. The committee recruited 88 companies around the world to act as registrars for its .firm, .shop, .web, .arts, .rec, .info and .nom domains. The US government has still to give the system its blessing, and may yet push ahead with its original scheme. Despite this, the 88 registrars have been taking applications for several months. They are due to start registering names this month with the Internet Council of Registrars, which grew out of the ad hoc committee.
To prevent conflicting names from being registered, the council will take one name from each registrar in turn before going back for the second name in their queues, and so on. This has led to a flourishing trade, with companies trying to buy a place near the head of the queue. Global Names of Singapore is charging $10, 000 to make sure a request for a name is the first one it sends off to the central database. Other registrars are charging nonrefundable deposits for places at the top of the queue. David Maher, chairman of the Policy Oversight Committee that is helping to set up and oversee the system, says that all registrars are subject to local laws regarding consumer protection and competition. But he says that the committee “will not act as an enforcement body in this are A.”
1. The domain name “.edu” is operated by
A. the US government.
B. the company Nerwork Solutions.
C. Internet Council of Registrars.
D. both A and B.
2. The .firm, .shop, .web, .arts, .rec, .info and .nom domains are NOT run by
A. a temporary committee organized by Internet's influential services.
B. the US government.
C. 88 registrars.
D. Internet Council of Registrars.
3. Global Names of Singapore is
A. a company which applies for a name on the Internet.
B. a registrar.
C. a company under the supervision of Policy Oversight Committee.
D. the central database.
4. How can a company successfully register a name with the Internet?
A. It must pay up to $10, 000 or a nonrefundable deposit.
B. Its application must be the first one at the top of the registration queue.
C. It must get approval from the Policy Oversight Committee.
D. Both A and B.
5. What is the meaning of the phrases “net cost” in the title?
A. The amount of money covering the basics.
B. The registration fee for a domain name on the Internet.
C. The amount of money for the construction of a network in a company.
D. The amount of money paid to the Internet service annually.
Retinal Prosthesis Help the Blind Regain Eyesight
Famed singer Stevie Wonder can't see his fans dancing at his concerts. He can't see the hands of his audience as they applaud wildly at the end of his Superstition.
Blind from birth, Wonder has waited his whole life for a chance to see. Recently, Wonder visited Mark Humayan, a vision specialist. He thought that a new device currently being studied by Humayan might offer him that chance.
The device, a retinal prosthesis, is a tiny computer chip implanted inside a patient's eye. The chip sends images to the brain and allows some sightless people to see shapes and colors. Wonder hoped the retinal prosthesis might work for him. “I've always said that if ever there's possibility of my seeing,” said Wonder, “then I would take the challenge.”
Unfortunately for Wonder, that challenge will have to wait. Humayan explained that the device isn't ready for people who have been blind since birth. Their brains may not be able to handle signals from a retinal prosthesis because their brains have never handled signals from a healthy eye.
However the retinal prosthesis and other devices show great promise in helping many other sightless people who once had vision see again. Perhaps one day soon, some formerly sightless people may be in Wonder's audience looking up—and seeing him—for the very first time.
Wonder's willingness to take part in retinal prosthesis studies and the results of those studies are giving new hope to people who thought they would be blind for the rest of their lives. More than one million people in the United States are considered legally blind, meaning that their eyesight is severely impaired. Another one million are totally blind.
Two types of specialized cells in the retina—rods and cones—are critical for proper vision. Light enters the eye and falls on the rods and cones in the retinal. Those cells convert the light to electrical signals, which travel through the optic nerve to the brain. The brain interprets those signals as visual images. Rods detect light at low levels of illumination. For instance, rods allow you to see faint shadows in dim moonlight. Cones, on the other hand, are most sensitive to color. Some diseases can damage cells in the retina. For instance, macular degeneration causes blindness and other vision problems in 700, 000 people in the United States each year. The condition is caused by a lack of adequate blood supply to the central part of the retina. Without blood, the rods, cones, and other cells in the retina die.
Devices such as the retinal prosthesis won't prevent or cure our eye diseases, but they may help patients who have eye disorders regain some of their vision. Different forms of retinal prostheses are currently being developed. On one type, a tiny computer chip is embedded in the eye. The chip has a grid of about 2, 500 light-sensing elements called pixels.
Light entering the eye strikes the pixels, which convert the light into electrical signals. The pixels then send the electrical signals to nerve cells behind the retina. Those cells send signals via the optic nerve to the brain for interpretation.
Many people who have had a retinal prosthesis implanted say they can see shapes, colors, and movements that they couldn't see before. “If was great,” said Harold Churchey, who received his retinal prosthesis 15 years after he became totally blind. “To see light after so long—it was just wonderful. It was just like switching a light on.” （572 words. Current Science. April 7, 2000）
1. Why did Steve Wonder visit Mark Humayan?
A. He thought Mark's device might recover his eyesight.
B. He thought Mark might need his help in developing the device.
C. He thought Mark might want to listen to his Superstition.
D. He thought Mark might implant a chip into his right eye.
2. Whom is Mark's retinal prosthesis ready for?
A. For those who have been blind from birth.
B. For those who still have faint vision.
C. For the blind who once had eyesight.
D. For those who still have one healthy eye.
3. For detecting colors, we depend, in the first place, on
A. interpretation by the brain.
B. cones of the retina.
C. rods of the retina.
D. optic nerve.
4. Why does macular degeneration cause blindness and other vision problems?
A. Macular degeneration causes improper interpretation by the brain.
B. Macular degeneration makes the retina less sensitive to the light.
C. Macular degeneration changes the functions of rods and cones.
D. Macular degeneration causes inadequate supply of blood in the retina.
5. Which of the following statements about the function of retinal prosthesis is true according to the passage?
A. It can prevent some eye disorders.
B. It can cure some eye disorders.
C. It can help recover eyesight to some degree.
D. It can repair the damaged cones.