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1.
根据不同退化程度草原和不同开垦年限农田土壤137Cs放射强度分析结果表明:与轻度退化草原相比,中度退化和重度退化中的137Cs放射强度分别下降了21%和52%。草原土壤开垦后,137Cs放射强度明显下降,开垦7年、15年、33年后,137Cs的放射强度分别只有轻度退化草原的37%、31%和26%。相关分析表明,伴随着土壤侵蚀的发生,土壤有机质含量、全N含量以及阳离子交换量下降。137Cs放射强度与土壤有机碳、土壤全N、交换性K和阳离子交换量呈极显著的正相关。  相似文献   
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The lead time compression is the core of supply chain management with time competition and the powerful source of competitive advantage of supply chain.As an emerging technology,The Internet of things ...  相似文献   
3.
围绕我国林业编制温室气体清单这一重要工作,介绍了IPCC关于LULUCF温室气体清单编制系列技术指南的技术要点和要求,阐明了我国林业温室气体清单编制工作的进展,提出了林业开展LULUCF碳监测工作未来面临的需求。同时,在分析美国、欧盟、加拿大等发达国家LULUCF温室气体清单编制做法和经验的基础上,提出了"在森林资源清查样地系统上构建"、"新布设LULUCF大样地系统"等2种开展LULUCF碳监测的思路,目的是为推动我国林业LULUCF碳监测达到国际先进水平提供建议。  相似文献   
4.
ObjectiveBedinvetmab, a fully canine anti-nerve growth factor monoclonal antibody, was evaluated in dogs for control of osteoarthritis-related pain in a study conducted to support registration in the USA.Study designRandomized, double-blind, placebo-controlled, multicenter, parallel-group study.AnimalsGeneral practice client-owned dogs with osteoarthritis (n = 272).MethodsDogs were block randomized 1:1 to placebo (saline, n = 137) or bedinvetmab (n = 135; 0.5–1.0 mg kg–1) administered subcutaneously, once monthly. The primary end point, day 28 Canine Brief Pain Inventory (CBPI) treatment success (TS), required pain severity score (PSS; 0–10) decrease ≥1 and pain interference score (PIS; 0–10) decrease ≥ 2. CBPI TS rates [and number needed to treat (NNT)], change in scores [and standardized effect size (ES)], change in quality of life (QoL) and bedinvetmab half-life were calculated.ResultsSignificant (p < 0.05) improvement with bedinvetmab over placebo occurred (days 28, 42, 56, 84) for CBPI TS. Of cases evaluable for day 28 CBPI TS (placebo, n = 131; bedinvetmab, n = 128), success rates were 36.6% and 47.4%, respectively (p = 0.0410) (NNT, 9.3; PSS and PIS ES, 0.3). CBPI TS increased after the second dose in both groups, plateaued for bedinvetmab at day 42 and decreased for placebo beginning day 84. Day 84 NNT (4.3), PSS (0.4) and PIS (0.5) showed continued improvement with monthly dosing. After the first dose, mean (± standard deviation) bedinvetmab half-life was 19.1 (8.3) days. Adverse events were similar between groups and not considered treatment-related. There was a significant effect of bedinvetmab versus placebo on all CBPI components (PIS, PSS, QoL).Conclusions and clinical relevanceThese results corroborated those previously reported and provide further support of safety and effectiveness of bedinvetmab (0.5–1.0 mg kg–1) administered subcutaneously at monthly intervals to dogs for control of osteoarthritis-related pain.  相似文献   
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It is important for enterprises' inventory management to find out the optimal production cycle and the length of shortage time,so that the total cost of inventory system can be reduced and the service level can be raised.Based on the classical EPQ model,this paper develops an EPQ model for deterioration items with different lost sale factor relative to the inventory level during shortage period.The existence of unique optimal solution is discussed by mathematic analysis and a numeric example.The sensitivity analysis shows that the parameter of losing sale has different impact on the costs of inventory system.The factors must be considered for the production inventory system to make management decision.  相似文献   
7.
基于Landsat Vegetation Continuous Fields(LVCF)、MODIS Vegetation Continuous Fields(MVCF)和MODIS Land Cover(MODLC)等遥感产品和森林清查数据(NFI)检测2000-2015年黄土高原森林分布及变化。结果表明:1)2000-2015年黄土高原森林覆盖度升高,基于LVCF和MVCF的全区森林覆盖度均值分别由2000年的7.8%和9.6%增加到2015年的9.7%和13.2%。2)遥感产品估算的森林分布空间格局和面积差异较大,基于LVCF、MVCF和MODLC估算的黄土高原森林面积在2000年分别为726.6×104、604.7×104 hm2和325.1×104 hm2,2015年分别为926.2×104、998.3×104 hm2和400.1×104 hm2。3)遥感产品估算的省级尺度上森林面积与NFI的不一致性因省份和年份而异,LVCF与NFI一致性整体略优于MVCF,MODLC与NFI差异最大且估算的森林面积远低于LVCF、MVCF和NFI。4)遥感产品检测的陕西和山西2省的森林面积增加值与NFI一致性高于宁夏;基于遥感产品估算的宁夏森林面积及增加幅度均远低于NFI。  相似文献   
8.
在日益激烈的企业生存竞争中,针对乳制品生产企业如何选取合适的生产批量和库存水平的问题,提出了成本-时间-客户满意度的三目标优化模型。首先,考虑乳制品的库存费用、周转时间和客户满意度,分别建立库存生产成本、库存周转时间和客户满意度优化模型;其次,以生产批量和库存水平为决策变量,应用多目标遗传算法,集成库存生产成本模型、库存周转时间模型和客户满意度模型,求出所有非劣解;最后,应用伪权向量法,通过保质期不同的产品验证提出的模型。结果表明,对于不同保质期的产品,均可得出最优库存生产批量大小和最优库存水平。  相似文献   
9.
The semiarid regions of Spain, including the central part of the Ebro River basin, are under threat due to desertification. Severe erosion, as a result of poor land management, has led to degradation of the soil resource, and there is a clear need for quantitative erosion rate data to evaluate the problem. This study aimed to examine the potential for using caesium-137 to identify the patterns and rates of soil erosion and redistribution within this semiarid environment. Samples for the determination of caesium-137 were collected from uncultivated slopes and cultivated valley floor sites near the head and outlet of a small representative basin in the Las Bardenas area. The measured patterns of caesium-137 mobilization, redistribution and export provide a semiquantitative indication of the variation in erosion within the study site. Calibration of the caesium-137 measurements, taking account of the differing behaviour of radiocaesium on cultivated and uncultivated land, allows estimation of the actual rates of erosion and deposition involved. The results show (1) the erosion rates on the cultivated land (1.6–2.5 kg m−2 yr−1) are typically more than five times those seen on the uncultivated land (0.2–0.4 kg m−2 yr−1), and (2) erosion on the uncultivated land is significantly less severe at the head of the basin than at the outlet. Study of the vegetation cover suggests that lower growing shrubs and grasses may be more effective in reducing erosion in this environment than trees.  相似文献   
10.
以ETM多光谱数据与SPOT5全色数据融合的遥感图像为对象,利用遥感图像和地面调查相结合的方法对吉林省东部山区进行森林资源调查,既可节约成本,又可提高调查精度,为遥感技术应用于森林资源调查设计探索了经验。  相似文献   
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