 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Study of Dropping Speed in Eggs of Oncomelania hupensis, a Snail Intermediate Host of Schistosomiasis) ผู้เขียน: Xingjian Xu, Xianxiang Yang, Xiapin Li, Wei Zhang, Qingsang Pan, Zhengan Xiong สื่อสิ่งพิมพ์:pdf AbstractOncomelana hupensis (Gredler, 1881) is an intermediate host of Schistosomiasis japonica in China. In order to understand the factors controlling sedimentation and drifting of adult snails and snail eggs in rivers, three aspects were investigated by experiment. Firstly, the specific gravity of the snail eggs which was found to be 2.29 g/cm3 ; secondly, the range of dropping speed of the snail eggs through a water column which was found to be 1.19 to 3.77 cm/s; thirdly, a formula to determine dropping speed of the eggs was established. The formula was statistically validated by comparison with observed values. The results are relevant to both the development and design of irrigation schemes, and also to river management, where dispersal of snails and their eggs needs to be controlled. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Experimental Measurement of Specific Gravity of Oncomelania hupensis and Its Eggs) ผู้เขียน:Xingjian Xu, Xianxiang Yang, Chuanhua Yu, Wei Zhang, Qingsang Pan, Zhengan Xiong สื่อสิ่งพิมพ์:pdf AbstractTo understand the distribution of Oncomelania hupensis, the intermediate host of Schistosomiasis japonicum, the specific gravities of the snails and their eggs must be known. When the specific gravities are known, the snail and its egg drop speed can be calculated and drift distance can be deduced in the river. The measurement of specific gravities of snails and eggs was carried out in accordance with the routine measures of specific gravity of river silt in China. The results indicated an average specific gravity for the live snails of 1.80 ? 0.01 g/cm3, and for snail eggs of 2.29 ? 0.01 g/cm3. The measured value of the specific gravity for the snails and its eggs must be considered when water condervancy facilities are disigned and/or rebuilt for prevention of the spread of snails in the endemic area of schistosomiasis. |