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Of 2, 000 commercial beekeepers in the United States about half migrate. Migratory beekeeping is nothing new. The ancient Egyptians moved clay hives, probably on rafts, down the Nile to follow the bloom and nectar flow as it moved toward Cairo. In the 1880s North American beekeepers experimented with the same idea. moving bees on barges along the Mississippi lighter, wooden hives kept falling into the water, Other keepers tried the railroad and horse drawn wagons, but that didn’t prove practical. Not until the 1920s when cars and trucks became affordable and roads improved, did migratory beekeeping begin to catch on. For the Californian beekeeper, the pollination season begins in February. At this time. the beehives are in particular demand by farmers who have almond groves; they need two hives an acre. For the three-week long bloom, beekeepers can hire out their hives for $ 32 each. By early March it is time to move the bees. It can take up to seven nights to pack the 4,000 or so hives that a beekeeper may own. These are not moved in the middle of the day because too many of the bees would end up homeless. But at night, the hives are stacked onto wooden pallets, back-to-back in sets of four, and lifted onto a truck. It is not necessary to wear gloves or a beekeeper’s veil because the hives are not being opened and the bees should remain relatively quiet. Just in case some are still lively, bees can be pacified with a few puffs of smoke blown into each hive’s narrow entrance. In their new location, the beekeeper will pay the farmer to allow his bees to feed in such places as orange groves. The honey produced here is fragrant and sweet and can be sold by the beekeepers. To encourage the bees to produce as’ much honey as possible during this period, the beekeepers open the hives and stack extra boxes called supers on top. These temporary hive extensions contain frames of empty comb for the bees to fill with honey. In the brood chamber below, the bees will stash honey to eat later. To prevent the queen from crawling up to the top and laying eggs, a screen can be inserted between the brood chamber and the supers. Three weeks later the honey can be gathered. Foul smelling chemicals are often used to irritate the bees and drive them down into the hive’s bottom boxes, leaving the honey-filled supers more or less bee free. These can then be pulled off the hive. They are heavy with honey and may weigh up to 90 pounds each. The supers are then taken to a warehouse where the extracting process takes place. After this, approximately a quarter of the hives weakened by disease, mites or an ageing or dead queen, will have to be replaced. To create new colonies, a healthy double hive, teeming with bees, can be separated into two boxes. One half will hold the queen and a young, already mated queen can be put in the other half, to make two hives from one. By the time the flowers bloom, the new queens will be laying eggs, filling each hive with young worker bees. The beekeeper’s family will then migrate with them to their summer location. To create new colonies, what will beekeepers do with the hives in good condition

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×发(2007)13号 ××乡政府关于禽流感会议的紧急通知 各单位: 春节刚过,与我市相邻的地区相继发现禽流感疑似病例,令人恐怖的禽流感正在逼近我市,人民生命财产和家畜性命受到极大威胁。在这千钧一发之际,我市上下闻鸡起舞,立即行动起来,一场拒禽流感于千里之外的人民战争拉开了序幕。为贯彻落实市委市政府关于全民动员、预防禽流感侵入我市的战略部署,拟于本周三上午在乡政府礼堂召开预防禽流感工作紧急会议。 以上通知,希相互传达。 ××市××县××乡政府 2009年3月1日 ××市××县××乡政府

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At the first sight the planet Mars does not appear very welcoming to 62. ______.any kind of life. It has very little oxygen and water, the temperature at night is below -50 degrees and winds of 100 miles per hour cause severe dusty storms. However, the surface of the planet seems to show that 63. ______.water flowed across at some time in the past, and it is believed that there 64. ______.is enough ice at the poles to cover the planet with water if il melts. 65. ______.Although there is no life on Mars. some scientists think that there may have some form of life a long time ago. At that time, the planet had active 66. ______.volcanoes; the atmosphere was thinner and warmer; and there was water. 67. ______.In fact, in some ways Mars may have been different to earth, where life 68. ______.exists. Some people believe that Mars could support life in the future if the right conditions were produced. The first step would be to warm the planet used certain gases which trap the sun’s heat in the planet’s 69. ______.atmosphere. By warmth, water and carbon dioxide, simple plants could 70. ______.begin to grow, These plants could slowly make Mars habitable. It is established that the whole process might spend between 100,000 and 200,000 71. ______.years. In the meantime, people could begin to live on the planet in specialclosed environments. They would provide a lot of useful information aboutconditions on Mars and the problems connected with living there.

简述用机动法计算钢筋混凝土四边固定矩形双向板极限荷载的要奌及步骤。

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