东北黑土有机质和酶活性与土壤肥力的关系

在前人和我们以往工作的基础上,我们认为,研究土壤肥力,既要考虑“体质”(指比较综合地、全面地反映土壤肥力的基础物质的组成与特征),又要考虑“土体”(指耕层及其连接部分),才能找到接近实际的肥力指标。本项研究试图探索东北黑土中有机质和酶活性与土壤肥力的关系。     

Comment on "HST2 mediates SIR2-independent life-span extension by calorie restriction"

Calorie restriction (CR) increases life span in yeast independently of Sir2. Lamming et al. (Reports, 16 September 2005, p. 1861) recently proposed that Sir2-independent life-span extension by CR is mediated by the Sir2 paralogs Hst1 and Hst2. Contradictory to this, we find that CR greatly increases life span in cells lacking Sir2, Hst1, and Hst2, which suggests that CR is not mediated by Sir2, Hst2, or Hst1.     

A longitudinal study to identify constraints to dairy cattle health and production in rural smallholder communities in Northern Vietnam

The objective of the study was to investigate constraints to dairy cattle health and production in rural smallholder communities in northern Vietnam, one of the target areas of the Vietnam government's dairy development programme. A total of 99 dairy farms (11 per commune) were recruited from 9 of 32 communes in Ba Vi District, using random two-stage cluster sampling. After the initial questionnaire interviews were conducted, farms were visited at three monthly intervals over a period of 1 year. Information on several health and production parameters relating to the study cattle was collected. Using multiple indicator modelling, it was found that Fasciola infestation, farmers who had been involved in dairying for longer (not indicative of better management skills), larger herd size, and cattle being kept in a shed were linked to reduced reproductive performances.     

我国图书馆学科服务的难点与突破

大学与专业图书馆的学科服务发展很快,但在实践中也存在着一些难点,主要体现在学科服务的规划与设计、确立学科服务的基点、学科馆员的角色、学科服务的系统性和协调性、学科服务考核方法等。为此,要从机制上寻求对这些难点的突破,重点是加强学科馆员团队建设,学科馆员工作要循序渐进,需要馆领导的强有力支持和其他部门的积极配合,融入一线具有不可替代性,加强以用户满意度为中心的效果考核。     

黑木耳新品种F-1号区域试验简报

黑木耳F-1号是由吉林省农作物新品种审定委员会于2008年审定的高产优质黑木耳(Auricularia auricula)新品种,2009年对F-1号进行新一轮的区域试验,结果表明,利用周转棒封口,提高了生产效率,降低了菌袋的污染率,提高了菌袋的成品率,污染率降至2%以下。F-1号干耳平均产量为467.60kg/万袋,比对照品种丰收2号增产14.86%,适合春秋栽培。     

陕甘山桃对根癌病的抗性评价

为评价陕甘山桃(Prunus davidiana var.potaninii Rehd)对根癌病的抗性,以实生钵苗为试材,采用人工接种的方法研究了其对根癌土壤杆菌(Agrobacterium tumefaciens Conn)和发根土壤杆菌(A.rhizogenes Conn)的抗性。结果表明:接种后60d,接种根癌土壤杆菌的陕甘山桃的株最大瘤径范围为0～10.1mm,平均瘤径2.7mm,接种发根土壤杆菌的株最大瘤径范围为0～11.6mm,平均瘤径3.0mm,根据抗性评价标准判定陕甘山桃群体高抗根癌土壤杆菌和高抗发根土壤杆菌。但陕甘山桃对根癌土壤杆菌和发根土壤杆菌的抗性存在广泛的的株间分离现象,均分离为免疫、高抗、中抗、低抗、感病和易感病6种类型,对根癌土壤杆菌免疫、高抗、中抗、低抗、感病和易感病型植株分别占群体总数的28%、33%、19%、13%、6%和1%,对发根土壤杆菌免疫、高抗、中抗、低抗、感病和易感病型植株分别占群体总数的16%、46%、15%、13%、8%和2%。陕甘山桃是优异的抗根癌病种质资源。     

土石坝洪水漫顶模糊风险分析

土石坝的安全性一直是备受关注的研究热点。洪水漫顶是影响大坝安全性的重要因素。对水库大坝洪水风险进行准确评估,可为保障水库大坝安全性提供理论依据。该文基于大坝漫顶风险分析理论,建立了漫顶失事模糊风险模型。并以新疆玛纳斯河夹河子水库为例,对其土石坝洪水漫顶模糊风险进行了评估,并得出主要结论:该水库大坝平均漫顶失事模糊风险率为5.02×10-3,超过了我国大坝风险评价标准,该坝的洪水漫顶破坏风险较大。     

杜鹃属常绿杜鹃组织培养的研究进展

常绿杜鹃树形优美,花色艳丽,具有较高的观赏价值和园林利用价值。但由于常绿杜鹃的繁殖困难,培育年限长,所以在市场上常常供不应求。随着植物组织培养技术的发展,近年来常绿杜鹃的组培快繁技术也有了一定的进展。现从常绿杜鹃组培快繁技术的外植体的选择、外植体的消毒方法、培养基的选择、不同激素对外植体的影响、增殖培养和生根培养以及生根苗移栽等方面作以综合性论述,以期为常绿杜鹃组培快繁技术提供借鉴。     

Changes of plasma endothelin-1 and von Willebrand factor in patients undergoing cerebral digital substration angiography

AIM: To investigate the effects of cerebral digital substration angiography (DSA) on the expression of endothelin-1(ET-1) and von Willebrand factor(vWF) in vascular endothelial cells from the patients with ischemic cerebrovascular disease. METHODS: The plasma levels of ET-1 and vWF were measured by enzyme-linked immunosorbent assay in 108 patients before, immediately and 24 h after cerebral DSA. RESULTS: The plasma level of endothelin-1 significantly increased immediately and 24 h after cerebral DSA as compared with that before the procedure (P<0.05). The level of vWF was not changed before and after operation. CONCLUSION: The marked and sustained increase in endothelin-1 plasma level after cerebral DSA is probably related to mechanical endothelial injury by the procedure of cerebral DSA.     

玫瑰引种及嫩枝扦插试验初报

通过玫瑰引种栽培试验,观测引种玫瑰的形态特征、生态适应性和其主要物候期;嫩枝扦插试验结果为NAA500mg/L和IBA250mg/L溶液处理玫瑰嫩枝插穗,能促进插穗生根;草炭:素沙=1:1混合基质能促进玫瑰扦插苗生长;筛选出四季玫瑰、转基因中天粉红和转基因中天粉白等适宜嫩枝扦插繁殖的玫瑰品种。