Weather experts use a scientific instrument called a barometer to measure pressure in Earth's atmosphere. But the device uses a barometer to estimate height. Instruments called magnetometers act as 3D compasses. They gather information about metallic structures.
The University of California scientists say they can create a virtual map with an accuracy of plus or minus 10 centimeters. They say the device uses a mathematical problem to add surfaces to the walls and floors. This can be used for architectural design or to run tests on energy usage.
Annie Marston says the device may be very useful to energy testers and engineers but also to builders and the constructionindustry.
\are closed up, so in later years you know where everything is,\
Researchers say they are now working to lower the weight of the backpack from 15 to about 10 kilograms. But the price of the device is about $20,000. Researchers predict the device will be available for loan at a much lower price.
I'm Jonathan Evans.
VOA's George Putic wrote this story from Washington. Jonathan Evans adapted it for Learning English. George Grow was the editor.
________________________________________________________________
Words in This Story
architect – n. a person who designs buildings
backpack – n. a container or bag for carrying things that is carried on someone's back
dimensional – adj. relating to height, length or width
disperse – v. to go or move in different directions; to spread apart
compass – n. a device to help the user identify direction
virtual – adj. existing or occurring on computers or on the Internet
accuracy – n. freedom from mistake; the ability to work without making mistakes
construction – n. the business of building things; the building trade
2015/5/24 Study: Insecticide Is Killing Wild Bees
By VOA 24 May, 2015
From VOA Learning English, this is the Environment and Science Report.
A new study says a widely-used insecticide is damaging wild bee populations. Wild bees are important, because they pollinate crops and wild plants.
Environmentalists in the United States and Europe say chemicals called neonicotinoids are causing a drop in the number of bees.
These insecticides are among the most commonly-used worldwide. Farmers often use seeds treated with the insecticides.
The chemicals target insects that eat crops, and they do not spread beyond the field. But they do get into pollen and nectar, which is where the bees come into contact with them.
Maj Rudlof is a researcher at Lund University in Sweden. She led the neonicotinoids study.
She and other researchers studied bees in fields. Half of the fields were grown from seeds treated with neonicotinoids. The other half was grown with seeds that were not treated. She spoke about the results of the study in a video released by the journal Nature, which published it:
\dramatic result we found was that bumblebee colonies almost didn't grow at all at the treated sites compared to the controlled sites.\
She says there were about half as many wild bees per square meter in treated fields as in untreated ones.
Dennis vanEngelsdorp is an entomologist, a scientist who studies insects. He works at the University of Maryland. He was not involved with the research on neonicotinoids. But, he says banning the chemicals may not be the answer. He says they are not as bad as other insecticides. He spoke to VOA on Skype.
\farmers to use products that may either be just as bad or worse.\
He says farmers often use the chemicals too much, and that may be hurting bees. Mr. vanEngelsdorp thinks farmers might not need to stop using neonicotinoids completely. He says the chemicals should be used more sensibly, or, in other words, only when necessary.
The same chemicals are thought to be linked to a problem with European honeybees – the bees kept by farmers to pollinate crops. The problem is called Colony Collapse Disorder. The worker bees from a beehive, or colony, suddenly disappear. Farmers do not see the dead bees around the hive.
A United States Department of Agriculture report included information about the effects of neonicotinoids. It said the chemicals make the bees more likely to become sick. The bees cannot fight the viruses that commonly affect them.
And that's the VOA Learning English Environment and Science Report. I'm Marsha James.
VOA Science and Agriculture Correspondent Steve Baragona reported this story from Washington. Christopher Jones-Cruise adapted it for VOA Special English. Caty Weaver was the editor.
_____________________________________________________________
Words in This Story
insecticide – n. a chemical substance that is used to kill insects
pollinate – v. to give (a plant) pollen from another plant of the same kind so that seeds will be produced
nectar – n. a sweet liquid produced by plants and used by bees in making honey
dramatic – adj. sudden and extreme
2015/5/24 America’s Famous Front Lawn Gets Overhaul
By VOA 24 May, 2015
Almost two kilometers of green grass stretch from the front of the U.S. Capitol building to the Washington Monument. Thousands of people walk on it every day. They also play games, have picnics, run their dogs and bike.
The activities have damaged the expanse of land known as the National Mall. Now workers are in the middle of a $45 million project to return thick, healthy grass to the area.
\
That is Michael Stachowicz. He is a man who knows his grass. Stachowitz spent 20 years caring for golf courses. Now, hemanages one of the best-known green spaces in the world.
\
More than twenty-five million people visit the Mall each year for concerts, festivals and rallies, and, of course, to visit its popular museums. Over the years all those feet have compressed the soil to the density of brick. Only weeds can succeed in the rock-hard soil.
The whole Mall is in a very poor condition. But the repair project is rebuilding it, from the ground up. The old soil will be replaced with new soil like you'd find under a professional baseball field.
The workers are even improving the grass itself. University researchers are helping to find the highest quality grasses for the space.
\ turf in the world, we're trying to find the most traffic-resistant, the toughest turf that we can.\
Workers are also burying devices called cisterns that will capture nearly four million liters of rainwater. Michael Stachowicz says they will help reduce pollution during heavy storms.
Sometimes, storm waters flood waste sewers. Then that water and the waste flow directly into the Potomac River, polluting it.
The cisterns will help prevent that.
The dig of such a huge stretch of ground has been a complex effort.
\
The job of rebuilding the Mall is expected to be completed by early 2017.
Hundreds of thousands of people will again walk all over it to attend the presidential inauguration in front of the Capitol.
I'm Jim Tedder.
VOA science correspondent Steve Baragona reported this story from Washington. Caty Weaver adapted it for VOA Learning English. Hai Do was the editor.
_____________________________________________________________
Words in This Story
picnic – n. a meal that is eaten outdoors especially during a trip away from home
manage – v. to have control of; to take care of and make decisions about
yard – n. an outdoor area that is next to a house and is usually covered by grass
compress – v. to press or squeeze (something) so that it is smaller or fills less space
turf – n. the upper layer of ground that is made up of grass and plant roots
2015/5/24 Memorial Day: Arlington National Cemetery
By Shelley Gollust and Christopher Jones-Cruise 24 May, 2015
Memorial Day is a national holiday observed in the United States on the last Monday in May. It is the day when Americans honor the women and men who have served in the military.
The Memorial Day holiday was first observed in 1868. The holiday was called Decoration Day. The observance was at what was then known as the National Cemetery in Arlington, Virginia, across the Potomac River from Washington, D.C.
It is now known as Arlington National Cemetery.
Soldiers with the 3rd U.S. Infantry Regiment, also known as The Old Guard, places flags at grave sites at Arlington National Cemetery.
More than four million people visit the cemetery every year.
It is the most famous national burial place in the United States. It includes about 250 hectares of rolling hills, and trees that were planted hundreds of years ago. There are more than 8,000 trees of 300 species in the cemetery. Up and down the hills are lines of simple white headstones marking the graves. About 400 of the markers have gold letters on them. These are the burial places of those who have been awarded the Medal of Honor, the nation's highest military honor.
Among those buried at the cemetery are military and political leaders, cabinet officers and Supreme Court justices. Astronauts, explorers and athletes are also buried there. So are chaplains, nurses, slaves and even war correspondents.
Arlington is on the land that once belonged to George Washington Parke Custis, a step-grandson of George Washington. The cemetery holds the graves of soldiers who died in every war in American history. Some who fought and died in the Revolutionary War in the 1700s were moved there from a nearby cemetery.
The first military burial was on May 13, 1864 for Private William Christman, who died in the Civil War. On May 15, 1864, two unknown Union Soldiers were buried at Arlington. They were the first of almost 5,000 unknowns who are now buried at the cemetery. On March 4, 1921, Congress approved the burial of an unidentified American soldier from World War I. It is now the site of the famed Tomb of the Unknown Soldier.
Nearly 4,000 former slaves are buried at Arlington National Cemetery. One of them is James Parks. He dug the first graves in the cemetery. And he is the only person buried there who was also born on the property.
Two American presidents are buried at Arlington National Cemetery. William Howard Taft was president in the early 1900s. John F. Kennedy was president in the 1960s. More people have visited his grave than any other in the United States.