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101.
为评价马铃薯中吡蚜酮残留引发的膳食风险。2016年-2018年开展了3年12地规范残留试验,构建吡蚜酮在马铃薯中的残留检测方法,并对我国一般人群进行了膳食风险评估。马铃薯样品使用2%乙酸乙腈提取,C18净化,外标法定量,UPLC-MS/MS检测。在0.01~1 mg/kg添加水平下,吡蚜酮在马铃薯中的平均回收率为75%~85%,相对标准偏差为3%~8%。12地最终残留试验表明,50%吡蚜酮水分散粒剂按有效成分225 g/hm2施药2次,最后1次施药后14、21 d马铃薯中吡蚜酮残留量分别≤0.018 mg/kg和≤0.012 mg/kg。膳食风险评估表明,吡蚜酮的国家估算每日摄入量(NEDI)为1.633 9 mg/kg,风险商(RQ)为86.4%。马铃薯中吡蚜酮残留不会对一般人群健康造成不可接受的风险。 相似文献
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103.
Alfredo Manicardi Laura Scarabel Josep María Llenes José María Montull María Dolores Osuna Joel Torra Farré Andrea Milani 《Pest management science》2023,79(12):4886-4896
BACKGROUND
Amaranthus palmeri is an aggressive annual weed native to the United States, which has become invasive in some European countries. Populations resistant to acetolactate synthase (ALS) inhibitors have been recorded in Spain and Italy, but the evolutionary origin of the resistance traits remains unknown. Bioassays were conducted to identify cross-resistance to ALS inhibitors and a haplotype-based genetic approach was used to elucidate the origin and distribution of resistance in both countries.RESULTS
Amaranthus palmeri populations were resistant to thifensulfuron-methyl and imazamox, and the 574-Leu mutant ALS allele was found to be the main cause of resistance among them. In two Spanish populations, 376-Glu and 197-Thr mutant ALS alleles were also found. The haplotype analyses revealed the presence of two and four distinct 574-Leu mutant haplotypes in the Italian and Spanish populations, respectively. None was common to both countries, but some mutant haplotypes were shared between geographically close populations or between populations more than 100 km apart. Wide genetic diversity was found in two very close Spanish populations.CONCLUSION
ALS-resistant A. palmeri populations were introduced to Italy and Spain from outside Europe. Populations from both countries have different evolutionary histories and originate from independent introduction events. ALS resistance then spread over short and long distances by seed dispersal. The higher number and genetic diversity among mutant haplotypes from the Spanish populations indicated recurrent invasions. The implementation of control tactics to limit seed dispersal and the establishment of A. palmeri is recommended in both countries. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献104.
Maria Caridad Montalvo Villalba Chantal J. Snoeck Licel de los Angeles Rodriguez Lay Aurélie Sausy Dayesi Hernández López Marite Bello Corredor Barbara Marrero Sanchéz Judith M. Hübschen 《Zoonoses and public health》2023,70(1):58-68
Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination. 相似文献
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106.
基于土地利用/覆盖的甘肃省景观生态风险时空变化特征 总被引:1,自引:0,他引:1
甘肃省景观类型丰富多样,在中国西部地区的生态安全中起关键性作用,也为当地发展提供着重要的物质基础和生态服务。由于气候变化和人类不合理活动的影响,甘肃省部分地区生态环境的安全与稳定遭到严峻挑战。本研究基于欧洲航空局全球土地利用/覆盖数据(CCI-LC),利用动态度、转移矩阵方法分析了2005-2019年甘肃省土地利用/覆盖变化特征;通过构建景观生态风险指数并运用空间自相关分析法分析了景观生态风险的空间分布特征。结果显示:1)2005-2019年间,裸地面积减少最多,变化率1.88%,耕地次之,变化率2.31%;草地面积增加最多,变化率1.83%,建设用地次之,变化率191.08%。2)所有土地利用/覆盖类型中,建设用地的动态度最高且在整个研究时期内变化速率都保持在较高水平,综合动态度最大的时期为2010-2019年。3)土地利用/覆盖转移矩阵主要表现为耕地、林地、草地、裸地之间的转入与转出以及其他土地类型向建设用地的转入。4)2019年整体的生态风险值较2005年明显上升。其中低风险区和较低风险区面积最多,转化最频繁;中等风险区、较高风险区和高风险区面积虽然较少,但都存在不同程度的增长。... 相似文献
107.
科技推广作为农业综合开发土地治理项目的一项重要措施,应全面融入于项目区的整体建设之中。必须正确把握国家农业综合开发科技推广的特征与要求,实现思维定势上的创新;国家把解决“三农”问题放在各项战略任务的首位,强调坚持统筹城乡经济社会发展,扎实推进社会主义新农村建设。必须正确理解和准确把握社会主义新农村建设的内涵,实现科技推广工作中技术构建上的创新;同时要正确把握农村现实状况,实现运行机制上的创新。 相似文献
108.
According to the security investment theory of Markowitz,this paper presents aCaculation method of portfolio investment under the risk minimization,and some mathematic expres-sions of the efficient frontier for portfolio investment are conducted.Based on these,the efficientfrontier is proved as a parabola,and a practical caculation process is given. 相似文献
109.
Credit risk, the major risk of bank, is more and more intense during the period of economic restructuring in China. In view of the flaw of present risk measurement system, Conditional Value-at-Risk is used for the credit risk measurement which is better than Value-at-Risk. This paper creates the model ,while gives the method and procedure for solving it. So CVaRof credit combination is produced, which is just the early warning value of credit risk. At last, it is concluded that the CVaRrisk measurement is too difficult to use widely at present in china, then some advice is provided. 相似文献
110.
Considering the character of slope resistant engineering invest benefit, in line with security and economy balmaced, combining initial investment and anticipated hazard loss, disaster resistant engineering should be satisfied with the criterion of minimum cost. Decision tree model is adopted as analyzing means, and risk decision-making of slope design is carried out. Project input-output radio adopting dynamic analysis can reflect project investment benefit more accurately. At last this paper analyzes some questions in process of slope resistant engineering with benefits enumerate. 相似文献