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81.
王秀芬  尤飞 《中国农学通报》2017,33(16):158-164
充分认识吉林省主要粮食作物生产面临的风险,为稳定粮食产量和保障国家粮食安全提供参考。以县级行政单元为研究对象,在运用直线滑动平均法对作物单产进行趋势模拟的基础上,运用非参数信息扩散模型对吉林省玉米、水稻和大豆3种主要粮食作物的生产风险进行了评估。结果表明:不同类型作物生产所面临的风险大小不同,单产损失风险从大到小依次为大豆、玉米、水稻;西北部地区县域的风险普遍较大,其次是东南角地区,而中部地区县域的风险相对较小;吉林省玉米、水稻和大豆3种作物单产损失率30%以上的概率较小。  相似文献   
82.
为最大程度地降低药品无菌工艺生产中微生物污染的风险,以重组溶葡萄球菌酶粉的生产过程为例,利用休哈特控制图、饼图统计工具、失效模式及影响分析(FMEA)风险工具对生产中操作人员可能引入微生物污染的五个因素(手套、前臂、胸口、前额、口罩)进行了监控和风险分析.试验结果表明,口罩的微生物检测结果最差,手套为污染的高风险因素.经过最差条件干预的培养基模拟灌装试验,验证了以预防为主的微生物质量控制措施可以有效控制无菌灌装生产工艺中人员对药品污染的风险.  相似文献   
83.
There have been several reported studies of wrasse health but none of these has shown transmission of wrasse diseases when stocked with farmed Atlantic salmon. Most of the studies have focussed on bacterial and parasite issues, including treatment of bacterial diseases with antibiotics and vaccination of wrasse. Classical and atypical furunculosis have been reported in wrasse following stress, and wrasse have been susceptible to vibrio infection. Further study is required on the vaccination of wrasse for furunculosis with latent carrier status to maximize survival. There are studies on viral diseases such as infectious pancreatic necrosis, infectious salmon anaemia and pancreas disease and although these did not give any undue concern for salmon health, there is also scope for further study in this area. Resident parasite communities of wrasse are largely host-specific and do not appear to be a threat to salmon. Given that wrasse have not, to date, been a vector of disease in salmon, attention should be placed on maintaining best practice in cohabiting wrasse with salmon. Other issues that should be addressed are good welfare of wrasse in pens and identifying measures of this, the identification of losses of wrasse in pens, being alert to potential emerging diseases through health screening of mortalities and assessing the risks associated with carrying forward wrasse from one salmon production cycle to the next. Issues of exploitation by fishing on wild wrasse stocks and improved biosecurity may be addressed by the increased movement by the industry to the stocking of farmed wrasse.  相似文献   
84.
刘晓明 《湖南农机》2007,(7):140-142
本文研究了现代风险导向审计在我国的运用前景,分析了依托我国最新的审计风险准则,发展现代风险导向审计的方法,提出了在我国推行现代风险导向审计的几条政策建议。  相似文献   
85.
冉小平 《湖南农机》2008,(3):178-179,181
本文叙述了可信计算系统的概念并提出对可信计算系统的不足和改进  相似文献   
86.
原料基地的战略价值研究--期权定价模型的应用   总被引:2,自引:0,他引:2  
肖平  张敏新 《林业科学》2004,40(6):165-169
在市场风险下 ,加工企业控制一定比例的原料供应 ,相当于购买了一种期权 ,这种期权对林工联合体有着不可忽视的战略价值 ,它可大大减少加工企业的市场风险暴露。本文应用期权定价模型对这种战略价值进行定量研究 ,敏感分析表明 :当木材市场价格水平、长期资本利率水平越高 ,木材价格波动率越大 ,加工企业拥有原料基地的战略价值越大。期权定价模型的应用为正确认识原料基地的战略价值 ,分析木材限额采伐政策等提供了良好的基础。  相似文献   
87.
After an absence of approximately 70 years, gray wolves (Canis lupus) were re-introduced into Yellowstone National Park in the mid-1990s. We studied the potential influence of wolf/ungulate interactions upon willow (Salix spp.) growth in the valleys of the Gallatin and Lamar Rivers, as well as Slough and Soda Butte Creeks, in the northern Yellowstone ecosystem. When we compared willow heights from photographs taken prior to 1998 (willows <2 m tall) with those taken in 2004, we found an increase in willow height for 22 of 42 sites within the study area. Based on comparisons of the chronosequence photos, since wolf introduction none of the 16 upland riparian sites showed an increase in willow height, while 22 of 26 of the valley-bottom riparian sites had willow height increases. In 2004, willow height exhibited a strong inverse relationship with the percentage of browsed stems (r = −0.81, p < 0.01, n = 42). Results of regressions for valley-bottom sites indicated that view distance, impediment distance, and the number of bison (Bison bison) flops were inversely related to willow height (p ≤ 0.02). Increased willow heights were not significantly (p = 0.18) related to patterns of moisture availability. Willow height increases documented in this study appear to have been at least partially due to behaviorally mediated trophic cascades involving wolves and ungulates, via a mechanism of predation risk. While willow release (i.e., increased height growth) within the study area is in a very early stage, results suggest potentially important indirect effects of a top carnivore in a terrestrial food chain that may aid in the restoration of riparian species and the preservation of biodiversity.  相似文献   
88.
Outbreaks of unexplained mortalities attributed to infectious salmon anaemia (ISA) were examined in the 1996 year class of Atlantic salmon in three regions of New Brunswick, Canada. A total of 218 net pens at 14 sites deemed to have been exposed to ISA virus (ISAV) were surveyed for mortality records and management, environmental and host characteristics. Based on definitions of mortality patterns, clinical ISA disease outbreaks occurred in 106 net pens. There were eight sites in which >50% of net pens experienced ISA outbreaks during the study period. Factors related to their potential role in transmission of virus to new sites or new net pens at the same site were identified as sea lice vectors, divers visiting multiple sites, sites belonging to companies with more than one site, exposure to other year classes at the site, and proximity to other infected net pens. Host resistance factors associated with greater risk of outbreaks were identified as larger groupings, general health following smolt transfer, stressful husbandry procedures during growout, and health or productivity during colder water periods. Despite very close proximity between sites, modification of these management factors would probably influence the severity of mortalities caused by ISAV.  相似文献   
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