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Climate change record in subsurface temperatures: A global perspective   总被引:2,自引:0,他引:2  
Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5 degreesC and that the 20th century has been the warmest of the past five centuries. The subsurface temperatures also indicate that Earth's mean surface temperature has increased by about 1.0 degreesC over the past five centuries. The geothermal data offer an independent confirmation of the unusual character of 20th-century climate that has emerged from recent multiproxy studies.  相似文献   
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Neptune's Story     
It is conjectured that Triton was captured from a heliocentric orbit as the result of a collision with what was then one of Neptune's regular satellites. The immediate post-capture orbit was highly eccentric with a semimajor axis a approximately 10(3)R(N) and a periapse distance rp that oscillated periodically above a minimum value of about 5R(N). Dissipation due to tides raised by Neptune in Triton caused Triton's orbit to evolve to its present state in less, similar10(9) years. For much of this time Triton was almost entirely molten. While its orbit was evolving, Triton cannibalized most of the regular satellites of Neptune and also perturbed Nereid, thus accounting for that satellite's highly eccentric and inclined orbit. The only regular satellites of Neptune that survived were those that formed well within 5R(N) and they move on inclined orbits as the result of chaotic perturbations forced by Triton. Neptune's arcs are confined around the corotation resonances of one of these inner satellites. The widths and lengths of the arcs imply that the satellite's radius is at least 30/(sin i)(2/3) kilometers for i less, similar 1, where i is the angle of inclination.  相似文献   
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目前,禽病防疫仍以疫苗免疫接种为主,疫苗安全性直接影响疫病防控效果,优质疫苗能预防疾病,提高家禽的生产性能,创造经济效益。相反,劣质疫苗可能对动物造成伤害,对环境造成污染,乃至威胁人类的健康。因此,选择安全高效的优质疫苗是做好家禽疫病防疫的关键。为保证疫苗质量安全,实行禽用活疫苗SPF化已经势在必行。  相似文献   
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The aim of this study was to evaluate the protective efficacy of the CIRCOQ porcine circovirus type 2 (PCV2) subunit vaccine in piglets with high maternally derived antibodies (MDAs) against disease caused by natural infection with PCV2d. A total of 130 weaned, 21-day-old healthy pigs was allocated into 3 trial groups. The signs of respiratory disorder were higher in unvaccinated pigs than in vaccinated pigs at 13 to 17 weeks old (P < 0.05), 18 to 22 weeks old (P < 0.001), and 23 to 27 weeks old (P < 0.01). The unvaccinated pigs had an early rate of dermatitis at 8 to 12 weeks old (10.0%), 13 to 17 weeks old (30.0%), 18 to 22 weeks old (46.7%), and 23 to 27 weeks old (33.3%), while there were no cases of dermatitis in vaccinated pigs. There was a significant difference (P < 0.05) in the mortality of pigs in the unvaccinated group and the 2-dosed vaccinated group. PCV2 viremia was detected in the blood and peaked at 105 days old in both unvaccinated pigs (Ct-adj = 8.40) and pigs vaccinated with 1 dose (Ct-adj = 6.37), while no detectable PCV2 virus was found in the blood of pigs vaccinated with 2 doses. At 77 and 105 days old, the PCV2 viremia load (Ct-adj) of unvaccinated pigs and those vaccinated with 1 dose was significantly higher (P < 0.05) than that of the 2-dosed vaccinated pigs. The body weight (BW), average weight gain (AWG), and average daily gain (ADG) in both groups of vaccinated pigs were significantly higher (P < 0.05) than those of unvaccinated pigs. The study vaccine was significantly efficacious in protecting vaccinated pigs against clinical symptoms, blood viral load, and mortality, as well as improving productivity, compared with unvaccinated pigs.  相似文献   
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