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耕牛轮牧对控制草洲感染性钉螺效果的研究 总被引:5,自引:5,他引:5
目的:探索耕牛轮牧对控制草洲感染性钉螺的效果。方法:选择翻阳湖中,重度疫区进贤县的军山湖乡为实验区,将该乡草洲划分为耕牛放牧区和禁牧区,每隔1两区轮换,耕牛进入放牧区前普治1次,同时,选择三里乡丰富行政村为对照区,耕牛敞放于草洲,每年普治1次,结果:实施安全轮牧的9块有螺草洲中,试前3块无感染螺,度后连续2年亦未发现感染螺,试前6块有感染螺的草洲,试后2年4块草洲感染性钉螺逐年下降到0,另外2块距村较近的]草洲仍有感染螺,感染螺放面下降了84.90%,耕牛感染率亦下降81.115,对照区6块草洲,试后2年感染螺面积下降20.83%,感染螺面积占有螺划洲面积的71.60%,耕牛感染率下降不显著,结论:草洲耕牛实施轮牧能有效地控制感染性钉螺密度,但离村较近草洲耕牛难以实施禁牧,感染螺密度得不到有效的控制。 相似文献
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通过在塔城市北山铁列克提春秋牧场设置的轻度放牧(BA1)、中度放牧(BA2)、重度放牧(BA3)和对照四个水平放牧的测定,对不同放牧强度下草地植被的盖度、高度、密度以及生物量的变化进行了研究。结果表明:草地植被群落的主要优势种是草原苔草、千叶蓍、三叶草、早熟禾;不同放牧强度对植物群落具有一定的影响,其中草地植被群落盖度、密度和地上生物量随着放牧强度的增强均呈现下降趋势。 相似文献
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洞庭湖区围栏封洲禁牧控制血吸虫病效果 总被引:1,自引:2,他引:1
目的观察洞庭湖区实施围栏封洲禁牧控制血吸虫病的效果。方法选择洞庭湖区沅江市冯家湾村为观察试点,调查围栏封洲禁牧前后人、畜、钉螺血吸虫感染率,家畜传染源数量和饲养方式,洲滩野粪分布,水体感染性,人畜在洲滩的活动情况,实施成本及其经济效益。结果围栏封洲禁牧2~5年后,人、畜、钉螺血吸虫感染率分别下降了88.89%、100%、100%,耕牛数量减少了73.60%,敞放饲养户减少了100%,舍饲圈养户增加了88.58%,人畜在洲滩的活动及污染减少,水体安全性增强,滩地生态经济效益提高了15%~20%。结论围栏封洲禁牧对控制湖区血吸虫病疫情具有积极作用。 相似文献
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Nazmul Hasan Thi Minh Hai Nguyen Karsten Busse Jörg Kressler 《Macromolecular chemistry and physics.》2023,224(7):2200428
A perfect isotactic poly(methacrylic acid) (it-PMAA) is synthesized and characterized by NMR spectroscopy. Surface pressure versus mean area per repeat unit (π−A) isotherms are recorded and compared with atactic poly(methacrylic acid) (at-PMAA). it-PMAA exhibits a π−A isotherm, indicating the formation of a stable Langmuir film. The isotherm has a characteristic pseudo-plateau at π of ≈11–14 mN m−1 attributed to the creation of worm-like entities confirmed by atomic force microscopy (AFM) in Langmuir–Blodgett (LB) films. These structures transform into spherical nanoparticles of ≈40 to 80 nm seen in LB films transferred at the end of the pseudo-plateau of the isotherm. Grazing incidence wide-angle X-ray scattering (GI-WAXS) shows a broad scattering signal (halo-like) at a q position of ≈11.12 nm−1, revealing the amorphous nature of the nanoparticles. An ordered morphology, however, is observed in thin films prepared by precipitating it-PMAA from dimethylformamide (DMF) solution under vigorous stirring and coating them on a solid support. Optical microscopy (OM), AFM, and GI-WAXS reveal more details about the structure. Finally, various structural modifications of PMAAs are explained based on their tacticity and the subsequent hydrogen bonding effects between the carboxylic acid groups. 相似文献