ADHD Linked to Air Pollutants
Children have an increased of attention problems,seen as early as grade school.If their noses inhaled(吸入)a certain type of air pollution when they were pregnant.That's the finding of a new study.Released when things aren't burned completely,this pollution is known as polycyclic aromatic hydrocarbons,or PAHs.The biggest sources of these PAHs:the burning of fossil fuels,wood and trash.
Frederica Perera works at Columbia University's Mailman School of Public Health is New York City.She researches how exposure to things in the environment affects children's health in a new study,she and her team studied the exposure to air pollution of 233 nonsmoking pregnant women in New York City.Because burning tobacco can spew(排放)PAHs into the air and lungs,Perera's team focused on nonsmokers.The researchers wanted to probe(探查)other sources of PAHs,ones that's would have been hard for an individual to avoid.
The team started by testing the blood of each woman during pregnancy.The reason Any PAHs in a woman's blood would also be available to the baby in her womb.Nine years later,the researchers investigated signs of attention problems in those children,now age 9.They asked each child's mother a series of questions.These included whatever her child had problems doing things that needed sustained(長(zhǎng)期的)mental effort,such as homework or games with friends.The scientists also asked if the kids had trouble following instructions or made frequent,careless mistakes.All of these can be symptoms of a disorder called Attention Deficit Hyperactivity Disorder,or ADHD.About one in U.S.children has ADHD.
Among the women studied,traffic and home heating were the primary sources of air pollution exposure,Perera and her team suspect.Some of these women had low levels of PAHs in their blood.Ohters had high levels.Those with high levels were five times as likely to have children who showed attention problems by age 9.The new findings were published November 5 in the journal PLOS ONE.
16.Perera and her team chose nonsmoking pregnant women all over America.
A.Right
B.Wrong
C.Not mentioned
17.The main purpose of the research was to find out how exposure to PAHs played a role in harming the subjects' physical health.
A.Right
B.Wrong
C.Not mentioned
18.Nonsmoking mothers were selected because the effect of smoking on PAHs was unclear.
A.Right
B.Wrong
C.Not mentioned
19.The blood of each woman was tested once a month during pregnancy.
A.Right
B.Wrong
C.Not mentioned
20.Kids with ADHD commonly fail in school.
A.Right
B.Wrong
C.Not mentioned
21.The women with high levels of PAHs in their blood were more likely to have kids with ADHD.
A.Right
B.Wrong
C.Not mentioned
22.Traffic and home heating were considered to be the biggest sources of PAHs for the subjects in the research.
A.Right
B.Wrong
C.Not mentioned
First Image-recognitions software
1）Dartmouth researchers and their colleagues have created an artificial intelligence software that uses photos to locate documents on the Internet with far greater accuracy than ever before.
2）The new system,witch was tested on photos and is now being applied to videos,shows for the first time that a machine learning algorithm（運(yùn)算法則）for image recognition and retrieval is accurate and efficienti enough to improve large-scale document searches online.The system uses pixel（像素）data in images and potentially video—rather than just text—to locate documents.It learns to recognize the pixels associatedwith a search phrase by studying the results from text-based image search engines.The knowledge gleaned（收集）from those results can then be applied to other photos without tags or captions（圖片說(shuō)明），making for more accurate document search results.
3）"Over the last 30 years,"says Associate Professor Korenzo Torresani,a co-author of the study,"the web has evolved from a small collection of mostly text documents to a modern,massive,fast-growing multimedia datastet,where nearly every page includes multiple pictures of videos.When a person looks at a Web page,he immediately get the gist（主旨）of it by looking at the pictures in it.Yet,sruprisingly,all existing popular search engine,such as Google or Bing,strip away the information contained in the photos and use exclusively the text of Wed pages to perform the document retrieval.Our study is the first to show that modern machine vision systems are accurate and efficient enough to make effective use of the information contained in image pixels to improve document search"
4）The researchers designed and tested a machine vision system—a type of artificialintelligence that allows computers to learn without being explicitly programmed—that extracts semantic（語(yǔ)義的）information from pixels of photos in Web pages.This informationg is used to enrich the description of the HTML page used by search engines for document retrieval.The researchers tested their approach using more than 600 search queries（查詢(xún)）on a database of 50 million Wed pages.They selected the text-retrieval search engine with the best performance and modified it to make use of the additional semantic information extracted by their method from the pictures of the Web pages.They found tht this produced a 30 percent improvement in precision over the original search engine purely based on text.
23.Paragraph 1 _____
24.Paragraph 2 _____
25.Paragraph 3 _____
26.Paragraph 4 _____
A.Popularity of the new system
B.Publication of the new discovery
C.Function of the new system
D.Artificial intelligence software created
E.Problems of the existing search engines
F.Improvementi in document retrieval
27.The new system does document retrieval by _____.
28.The new system is expected to improve precision in _____.
29.When performing document retrieval the existing search engines ignore _____.
30.The new system was found more effective in document search than the _____.
A.information in images
B.current popular search engines
C.using photos
D.machine vision systems
E.document search
F.description of the HTML page
Dangers await babies with altitude
Women who live in the world's highest communities tend to give birth to under-weight babies,a new study suggests.These babies may grow into adults with a high risk of heart disease and strokes.
Research has hinted that newborns in mountain communities are lighter than average.But it wasn't clear whether this is due to reduced oxygen levels at high altitude or because their mothers are under-nourished—many people who live at high altitudes are relatively poor compared with those living lower down.
To find out more,Dino Giussani and his team at Cambridge University studied the records of 400 births in Bolivia during 1976 and 1998.The babies were born in both rich and poor areas of two cities： La Paz and Santa Cruz.L Paz is the highest city in the world,at 3.65 kilometers above sea level,while Santa Cruz is much lower,at 0.44 kilometers.
Sure enough,Giussani found that the average birthweight of babies in La Paz was significantly lower than in Santa Cruz.This was true in both high and low-income families.Even babies born to poor families in Santa Cruz were heavier on average than babies born to wealthy families in lofty La Paz."We were very surprised by this result，"says Giussani.
The results suggest that babies born at high altitude are deprived of oxygen before birth."This may trigger the release or suppression of hormones that regulate growth of the unborn child，"says Giussani.
His team also found that high-altitude babies tended to have relatively larger heads compared with their bodies.This is probably because a fetus starved of oxygen will send oxygenated blood to the brain in preference to rest of the body.
Giussani wants to find out if such babies have a higher risk of disease in later life.People born in La Paz might be prone to heart trouble in adulthood,for example.Low birthweight is a risk factor for coronary（冠狀的） heart disease.And newborns with a high ratio of head size to body weight are often predisposed to high blood pressure and strokes in later life.
Why Buy Shade-Grown Coffee?
When people argue about whether coffee is good for health,they're usually thinking of the health of the coffee drinker.Is it food for your heart? Does it increase blood pressure? Does it help you concentrate? However,coffee affects the health of the human population in other ways,too.
Traditionally,coffee bushes were planted under the canopy（樹(shù)冠）of taller indigenous（土生土長(zhǎng)的）trees.However,more and more farmers in Latin America are deforesting the land to grow full-sun coffees.At first,this increases production because more coffee bushes can be planted if there aren't any trees.With increased production come increased profits.
Unfortunately,deforesting for coffee production immediately decreases local-wildlife habitat.Native birds nest and hide from predators（捕食者）in the tall trees and migrating birds rest there.
Furthermore,in the long term,the full-sun method also damages the ecosystem because more chemical fertilizers and pesticides are needed to grow the coffee.The fertilizers and pesticides kill insects that eat coffee plant,but then the birds eat the poisoned insects and also die.The chemicals kill or sicken other animals as well,and can even enter the water that people will eventually drink.
Fortunately,farmers in Central and South America are beginning to grow more coffee bushes in the shade.We can support these farmers by buying coffee with such labels as "shade grown"and "bird friendly."Sure,these varieties might cost a little more.But we're paying for the health of the birds,the land,ourselves,and the planet.I think it's worth it.
More Rural Research is Needed
Agricultural research funding is vital if the world is to feed itself better than it does now.Dr.Tony Fischer,crop scientist,said demand was growing at 2.5% per year but with modern technologies and the development of new ones,the world should be able to stay ahead.
"The global decline in investment in international agricultural research must be reversed if significant progress is to be made towards reducing malnutrition（營(yíng)養(yǎng)不良）and poverty."he said.
Research is needed to solve food production,land degradation（貧瘠化）and environmental problems.Secure local food supplies led to economic growth which is turn,slowed population growth.Dr.Fischer painted a picture of the world's ability to feed itself in the first 25 years,when the world's population is expected to rise from 5 X to X billion people.He said that things will probably hold or improve but there'll still be a lot of hungry people.The biggest concentration of poor and hungry people would be in sub-Saharan Africa and southern Asia in 2020,similar to the currenti pattern.If there is any change,a slighe improvement will be seen in southern Asia,but not in sub-Saharan Africa.The major improvement will be in East Asia,South America and South-East Asia.
The debeloping world was investing about 0.5%,or $8 billion a year,of its agricultural gross domestic product（GDP）on research and developed world was spending 2.5% of its GDP.Dr.Fischer said more was needed from all countries.
He said crop research could produce technologies that spread across many countries,such as wheat production research having spin-offs（有用的副產(chǎn)品）for Mexico,China or India.
"Technologies still need to be refined for the local conditions but a lot of the strategic research can have global application,so that money can be used very efficiently."Dr.Fischer said.
Yields of rice,wheat ad maize（玉米）have grown impressively in the past 30 years,especially in developing countries.For example,maize production rose from 2 to 8 tonnes per hectare between 1950 and 1995.But technologies driving this growth such as high-yield varieties,fertilizers,and irrigation,were becoming exhausted."If you want to save the land for non-agricultural activities,for forests and wildlife,you're going to have to increase yield."Dr.Fischer said.
Saving a City's Public Art
Avoiding traffic jams in Los Angeles may be impossible,but the city's colorful freeway murals（壁畫(huà)）can brighten even the worst commute.Paintings that depict（描述）famous people and historical scenes cover office buildings and freeway walls all across the city.With a collection of more than 2，000 murals,Los Angeles is the unofficial mural capital of the world.
But the combination of graffiti（涂鴉）,pollution,and hot sun has left many L.A.murals in terrible condition._____（46）In the past,experts say,little attention was given to caring for public art.Artists were even expected to maintain their own works,not an easy task with cars racing by along the freeway.
_____（47）The work started in 2003.So far,16 walls have been selected,and more may be added later.
Until about 1960,public murals in Los Angeles were rare.But in the 1960s and 1970s,young L.A.artists began to study early 20th-century Mexican mural painting._____（48）
The most famous mural in the city is Judith Baca's "The Great Wall,"a 13-foot-high（4-meter-high）painting that runs for half a mile （0.8 kilometer） in North Hollywood，_____（49）it took eight years to complete—400 underprivileged teenagers painted the designs—and is probably the longest mural in the world.
One of the murals that will be restored now is Kent Twitchell's "Seventh Street Altarpiece."which he painted for the Los Angeles Olympics in 1984._____ （50）Twitchell said,"It was meant as a kind of gateway through which the traveler to L.A.must drive.The open hands represent peace.”
Artists often call murals the people's art.Along a busy freeway or hidden in a quiet neighborhood,murals can reach people who would never pay money to see fine art in a museum,"Murals give a voice to the silent majority，"said one artist.
A.The mural represents the history of ethnic groups in California.
B.Artists like murals because they like the work of Mexican artists.
C.The city trying to stop the spread of graffiti,has painted over some of the murals complete.
D.Soon,their murals became a symbol of the city's cultural expressions and a showcase for L.A.'s cultural diversity.
E.This striking work depicts two people facing each other on opposite sides of the freeway near downtown Los Angeles.
F.Now the city is beginning a huge project to restore the city's murals.
I'll Be Bach
Composer David Cope is the inventor of a computer program that writes original works of classical music.It took Cope 30 years to develop the software.Now most people can't _____(51)the difference between music by the famous German composer J.S.Bach (1685-1750) and the Bach-like compositions from Cope's computer.
It all started in 1980 in the United States,when Cope was trying to write an opera.He was having _____(52)thinking of new melodies,so he wrote a computer program to create the melodies.At first this music was not_____(53)to listen to.What did Cope do? He began to rethink how human beings compose music.He realized that composers,brains_____(54)like big databases.First,they take in all the music that they have ever heard.Then they take_____(55)the music that they dislike.Finally,they make new music from what is_____(56).According to Cope,only the great composers are able to create the database accurately,remember it,and form new musical patterns from it.
Cope built a_____(57)database of existing music.He began with hundreds of works by Bach.The software analyzed the dataa_____(58)it down into smaller pieces and looked for patterns.It then combined the_____(59)into new patterns.Before long,the program could compose short Bach-like works.They weren'tgood,but it was a start.
Cope knew he had more work to do-he had a whole opera to write.He continued to improve the software.Soon it could_____(60)more complex music.He also added many other composers,including his own workto the database.
A few years later,Cope's computer program,called "Emmy",was ready to help him with his opera.The_____(61)required a lot of collaboration between the composer and Emmy.Cope listened to the computer's musical ideas and used the_____(62)that he liked.With Emmy,the opera took only two weeks to finish.It was called Cradle Falling,and it was a great_____(63)! Cope received some of the best reviews of his career,but no one knew exactly_____(64)he had composed the work.
Since that first opera,Emmy has written thousands of compositions.Cope still gives Emmy feedback on what he likes and doesn't like of her music,_____(65)she is doing most of the hard work of composing these days!
51._____
A.Make
B.tell
C.Take
D.understand
52._____
A.trouble
B.time
C.fear
D.pleasure
53._____
A.Loud
B.peaceful
C.classic
D.easy
54._____
A.Feel
B.look
C.sound
D.work
55._____
A.in
B.at
C.with
D.out
56._____
A.added
B.left
C.created
D.released
57._____
A.Small
B.huge
C.Simple
D.colorful
58._____
A.cut
B.drop
C.broke
D.turned
59._____
A.parts
B.programs
C.ideas
D.pieces
60._____
A.play
B.hear
C.collect
D.analyze
61._____
A.stage
B.process
C.period
D.application
62._____
A.ones
B.cases
C.others
D.sides
63._____
A.loss
B.end
C.success
D.rush
64_____
A.when
B.how
C.what
D.why
65._____
A.but
B.until
C.so
D.because