单词:3-amino-1-pyrazole
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This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute. As Valentines day approaches, remember, its the thought that counts. Just ask a decorated cricket. Because according to a study published in the January
The penguins stay when all other creatures have fled because each guards a treasurea single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach. There is no food and no water for them. And they will not see the sun
Egyptian archaeologists have discovered the bottom part of an unknown pyramid in the Sakkara area about 18 miles south of Cairo. NationalGeographic explorer-in-residence Dr. Zahi Hawass, the Secretary General of the Egyptian Supreme Council for Anti
Azaz Residents Pick Up After Aerial Bombings The residents of Azaz clean up and mourn after Wednesday's deadly bombing by Syrian government warplanes. Azaz had been peaceful in recent months, although forces of the rebel Free Syrian Army have had to
Egyptian archaeologists have discovered the bottom part of an unknown pyramid in the Sakkara area about 18 miles south of Cairo. National Geographic explorer-in-residence Dr. Zahi Hawass, the Secretary General of the Egyptian Supreme Council for Anti
They are constantly on the move. New-born calves have to be up and running the day they are born. But the vast herds do not travel alone. Wolves. Packs of them, eight to ten strong, shadow the migration. And they are hungry. Its the newly born calves
But they are hungry and eager to reach their mother whos delayed feeding them on this special day. Now she lures them with the promise of milk, the only food the cubs have known since they were born, deaf and blind beneath the snow some two months ag
Day 10. And the mother has let her cubs a mile from the den. Its time to put them to the test. Theyve grown enormously in confidence, but they dont have their mothers sense of urgency. At last it seems that they are ready for their journey. And they
Midsummer on the tundra and the sun does not set. At these altitudes, the suns rays are glancing and not enough of their energy reaches the ground to enable trees to grow. Youll need to travel five hundred miles south from here before that is possibl
As we travel south, so the suns influence grows stronger. And at 50 degrees of latitude, a radical transformation begins. Summers here are long enough for broadleaf trees to replace conifers. Broadleaves are easier to eat and digest, so now animals c
The advance of the seasons brings constant change. As the suns influence diminishes in the north, so the deciduous forests of America begin to shut down, losing their leaves in preparation for the dark, cold months ahead. One season hands over to ano
The character of the forest changes as we descend, becoming ever darker and damper, favoring different kinds of animals and plants. Less than two percent of the sunlight reaches the floor. But even here there is extraordinary variety. In the Great Is
The sun beating down on tropical waters powers the weather systems of the globe. Moisture evaporates from the warming ocean and rises to create great storms. The winds generated out at sea sweep inland across the continents. As they travel across the
Deer are frequent casulties of the harsh winter. And these leopards are not above scavenging from a corpse. African leopards could never survive here. But the Russian cats have thick fur to shied them from the cold. There are only 40 Amur leopards le
Their secret is teamwork. Impala are their favourite prey. They start to hunt and the pack splits up. An aerial viewpoint gives a new insight into their strategy. As the dogs approach their prey, they peel off to take up separate positions around the
The dogs know their prey must come out or drown. Now its a waiting game. The rest of the pack are calling. Theyve made a kill in the forest and this is an invitation to join in the meal. The impala is in luck. A pack this size kills once a day and ev
All across southern Africa, all animals are journeying for the same reason. Buffalo join the great track. Nowhere else on Earth are so many animals on the move for the same urgent purpose. They are all heading for the swamps of the Okavango, a vast i
Science and technology 科学技术 Creutzfeldt-Jakob disease 克雅氏病 Breaking down the barrier 攻破屏障 A glimmer of hope for a drug that treats disease caused by prions 药物治疗朊病毒感染疾病的一线希望 THE epidemic of mad-c
Science and Technology Creutzfeldt-Jakob disease Breaking down the barrier 科技 克雅氏病 攻破屏障 A glimmer of hope for a drug that treats disease caused by prions 药物治疗朊病毒感染疾病的一线希望 THE epidemic of mad-cow dis