ABSTRACT
Objective To study the relationship between environment selenium distribution characteristic and Kaschin-Beck disease (KBD) in the Yarlung Zangbo River banks and to provide some measures for prevention and control of KBD in the north side of the river bank.Methods Considering the geography and KBD distribution,we made a survey in Xietongmen (KBD area),Lazi and Sajia (non-KBD area) counties in 2013 and 2015.Water,soil,herbage,grain food and children hair samples were collected.Selenium of the samples was measured by hydride generation-atomic fluorescence spectrometry.Results A total of 246 samples of natural soil,cultivated soil,drinking water,food and forage,and 103 samples of children hair were collected.The selenium in natural soil,cultivated soil,herbage,barley,tsampa,self-produced wheat in non-KBD area in the south side of Yarlung Zangbo River bank were significantly higher than those in KBD areas in the north side [mean (μg/kg):288.62 vs 134.90,228.26 vs 160.28,41.85 vs 5.10,13.99 vs 4.02,12.64 vs 8.07,27.44 vs 13.56,U =7,23,0,19,62,0,P ＜ 0.05].Hair selenium in school children in KBD area in the north side was higher than that previously reported,but still significantly lower than that in non-KBD areas in the south side of the river bank [mg/kg:0.221 vs 0.306,U =650,P ＜ 0.01],and about 65.45％ (36/55)of school children in KBD area were at a risk of selenium deficiency in the north of the Yarlung Zangbo River bank.Conclusions The selenium contem in the food chain of soilplants-animals (human being) is significantly lower in KBD area in the north side of Yarlung Zangbo River bank than that in non-KBD areas in the south side.It's still a key factor for the occurrence and prevalence of KBD that low selenium in environment in KBD areas in the north side.
ABSTRACT
Objective To study the relationship between land use/cover structure and changes and risk of plague prevalence.Methods Chifeng,Aohan,Alukeerqin and Wengniute were selected as typical areas of Spermophilus Dauricus plague foci in Inner Mongolia,density of Spermophilus Dauricus,plague epidemic and land use data in 1986,1995,2000 were collected,and risk of plague prevalence was represented by the density of Spermophilus Dauricus and epizooty of Spermophilus Dauricus.The percentage of land type structure,change degree of integrated land cover,division index of grassland for plague suitable habitat were calculated with ArcGIS 9.3.The relationship between the land use,cover change and the plague epidemic were analyzed by the methods of comparative.Results From 1982 to 2000,the density of Spermophilus Dauricus was lower than 0.4/hm2 and no epizooty of Spermophilus Dauricus was observed both in Aohan Banner and Chifeng City,which indicated low risk of plague prevalence.Contrarily,from 1982 to 2000,the density of Spermophilus Dauricus was higher than 1.0/hm2,and epizooty of Spermophilus Dauricus was prevalent in Alukerqin Banner,which implied high risk of plague prevalence.In Wenguiute Banner,the density of Spermophilus Dauricus was lower than 0.3/hm2 from 1982 to 1990,after then showed a rising trend,reached higher than 1.0/hm2 in 1991,1995-1997,and epizooty of Spermophilus Dauricus was also monitored,which denoted high risk of plague prevalence;In 1986,1995 and 2000,the proportions of grassland of Wengniute Banner,Alukerqinqi Banner (51.36％,49.14％,48.28％;56.97％,57.48％,57.44％) were much higher than Chifeng and Aohan Banner (35.99％,33.24％,32.95％;38.94％,34.46％,31.31％),but those of arable land (16.81％,18.78％,20.22％;13.28％,14.92％,15.15％) were lower than Chifeng and Aohan Banner (39.73％,42.25％,42.67％;41.21％,43.99％,49.53％).The highest of comprehensively dynamic degree of land cover changes appeared in Aohan Banner,and it was 0.53 and 1.11 in 1986 vs.1995 and 1995 vs.2000,respectively,and the lowest in Alukeerqin Banner,it was 0.22 and 0.05 during those periods.The grassland division index in Alukeerqin Banner was the lowest,which was 0.29 in 1986,0.28 in 1995,and 0.29 in 2000.The grassland division index was higher and showed a upward trends in Aohan Banner,which was 0.57 in 1986,0.69 in 1995 and 0.71 in 2000.Conclusion There is a certain relation between risk of plague prevalence and land use/cover structure and changes.
ABSTRACT
Objective To investigate the cognitive difference between uni-modal (V,A) and bi-modal (VA)target stimuli from both vision and audition,and then to study the neural mechanisms of bi-modal enhancement.Methods This experiment adopted a speeded target stimuli detection task, both behavioral and electroencephalographic responses to uni-modal and bi-modal target stimuli which were combined from visual and auditory target stimuli,were recorded from 14 normal subjects using a 64-channel EEG NeuroScan system.The differences of cognitive between uni-modal and bi-modal stimulus were tested from both behavioral (reaction time (RT) and error rate (ER)) and event-related potentials (ERPs) (P2 latency and amplitude,P3 latency and amplitude)data,and the correlation between behavioral and ERPs results were analyzed.Results As a result,the RT,ER and P3 latency has significant difference between uni-modal and bi-modal target stimuli.In addition,there were significant correlation between behavioral data and P3 latency,especially from the RT and P3 latency.Conclusion By comparing the difference between uni-modal and bi-modal from both behavioral and ERPs results,we could reached the conclusion that the neural mechanism of bi-modal target detection was predominant over that of vision and audition uni-modal target detection,the enhancement take place not only involved in early ERP components (such as P1 and N1),but engaged at the late ERP components (such as P2 and P3).