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Artificial root exudates and soil organic carbon mineralization in a degraded sandy grassland in northern China

Journal of Arid Land 2014年第4期6卷 423-431页

作者： YongQing LUO XueYong ZHAO olof andrén YangChun ZHU WenDa HUAnG naiman Desertification and Farmland Research Station of the Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences University of Chinese Academy of Sciences Bjorklundavagen 3

Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/n ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical condu

关键词： artificial root exudates carbon mineralization pH variation deteriorated grassland ecosystem Inner Mongolia

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由标准气象站数据估计出的非洲撒哈拉以南土壤的气候和分解者活动:土壤碳平衡计算的一个简单气候指数

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AMBIO－人类环境杂志 2007年第5期36卷 361-368页

作者： olof andrén Job Kihara andré Bationo Bernard Vanlauwe Thomas Ktterer 王胜瑞典农业大学(SLU)土壤科学系热带农业国际中心热带土壤生物和肥力研究所 TSBF-CIAT 瑞典农业大学(SLU)

本文逐日计算了土壤的生物学活动,使用的是非洲气象站的标准气象数据、一个简单的土壤水分模型,并且使用了关于温度、土壤含水量和生物学活动之间关系的一般性假设。活动系数r_(e_clim)由日土壤湿度和温度计算得出,从而考虑了温度与湿... 详细信息

本文逐日计算了土壤的生物学活动,使用的是非洲气象站的标准气象数据、一个简单的土壤水分模型,并且使用了关于温度、土壤含水量和生物学活动之间关系的一般性假设。活动系数r_(e_clim)由日土壤湿度和温度计算得出,从而考虑了温度与湿度之间的交互作用。瑞典中部(粘壤土,无作物)r_(e_clim)的年均值标准化为1,在那里进行了最初的校准。由于土壤在储水能力和植物覆被上的差异会对蒸腾作用产生影响,所以我们选择的样地均为无作物的该土壤,这样就只包括了气候差异。瑞典r_(e_clim)值,1,相当于诸如表土中含有的谷类秸杆等的年质量亏损约50%。非洲r_(e_clim)年均值在干热地点(法亚,乍得)为1.1,温湿地点(布拉柴维尔,刚果)为4.7之间变动。肯尼亚样地的r_(e_clim)值为2.1(高海拔,Matanya)至4.1(肯尼亚西部,Ahero)。这意味着假如土壤类型和经营相同,那么必须有4.1倍于瑞典的碳输入才能将Ahero的土壤碳水平维持在瑞典水平。对每一块样地都绘制了r_(e_clim)日动态图,并讨论了年内动态差异。模拟实验表明,如果将土壤碳平衡的瑞典土壤移至肯尼亚的Ahero,30年内其土壤碳将损失41%。如果将Ahero保持碳平衡的土壤移至瑞典,30年内其土壤碳含量将增加64%。本文讨论了方法与结论的有效性,并将r_(e_clim)与其它气候指数进行了对比。本文还提出了一种对r_(e_clim)值进行粗略估计的简易方法。

关键词：气候指数土壤碳平衡计算标准化气象站非洲估计分解者

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Psychological and physiological impacts of a fast-track diagnostic workup for men with suspected prostate cancer:Preliminary report from a randomized clinical trial

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Cancer Communications 2020年第5期40卷 239-242页

作者： Jianwei Zhu Ruoqing Chen Sabina Davidsson Jessica Carlsson Anna Messing-Eriksson Jonna Fridfeldt Ove andrén Sven-olof Andersson Unnur Valdimarsdóttir Fang Fang Katja Fall Department of Orthopedic Surgery West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan 610000P.R.China Department of Medical Epidemiology and Biostatistics Karolinska InstitutetStockholm 17177Sweden Clinical Epidemiology and Biostatistics School of Medical SciencesÖrebro UniversityÖrebro 70185Sweden Department of Urology Faculty of Medicine and HealthÖrebro UniversityÖrebro 70185Sweden Department of Epidemiology Harvard T.H.Chan School of Public HealthBostonMassachusetts 02115SA Institute of Environmental Medicine Karolinska InstitutetStockholm 17177Sweden

Dear Editor,The increasing number of men who undergo workup for suspected prostate cancer are subject to severe emotional stress[1].Stress levels seem to be elevated as soon as a suspicion of cancer is raised and the waiting time before a final diagnosis may be equally stressful as the post-diagnostic period[1,2].We recently demonstrated a marked increase in risk for different psychiatric disorders during the six months before prostate cancer diagnosis,highlighting the potential impact of emotional stress experienced while waiting for the diagnosis[3].

关键词： diagnosis elevated emotional

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Variability of platelet aggregation in patients with clopidogrel treatment and hip fracture: A retrospective case-control study on 112 patients

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World Journal of Orthopedics 2015年第5期6卷 439-445页

作者： Anna Clareus Inga Fredriksson Hkan Wallén Max Gordon andré Stark olof Skldenberg Division of Orthopaedics Department of Clinical Sciences at Danderyd Hospital Karolinska Institutet Division of Anesthesiology Department of Clinical Sciences at Danderyd Hospital Karolinska Institutet Division of Cardiology Department of Clinical Sciences at Danderyd Hospital Karolinska Institute

AIM: To identify the rate of non-responders to clopidogrel treatment in hip fracture patients and study how non-responders differ from ***: In a retrospective case-control study we included 28 cases of acute proximal femoral fracture with clopidogrel treatment 2011 to 2013. Eighty-four controls from the same time period were included. Data collected included response to clopidogrel measured with multiple electrode aggregometry(MEA), intraoperative bleeding, erythrocyte transfusion, time to surgery and the incidence of adverse events up to 3 mo after surgery. RESULTS: Eight(29%) of the 28 cases were nonresponders. The median intraoperative bleeding was 300 mL(range, 0-1500), and was lower for non-responders(50 m L) but did not reach statistical significance. Erythrocyte transfusions did not differ between responders, non-responders and controls. Forty-five(40%) of 112 patients had adverse events postoperatively but the rate did not differ between patients with and without clopidogrel ***: Almost one-third of patients withclopidogrel treatment and an acute proximal femoral fracture are non-responders to antiplatelet therapy and can be operated without delay.

关键词： Proximal femoral fracture Clopidogrel Variability Bleeding Adverse events

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