基于最小数据集沂蒙山区不同治理模式下的土壤质量评价

沂蒙山区是北方土石山区水土流失治理重点区域,定量评价不同治理模式下的土壤质量,进而优选适宜的生态恢复措施,是推进沂蒙山区生态环境建设的关键。以沂蒙山区4种治理模式(乔草混交、土坎梯田+果树种植、撂荒、封禁植草)为研究对象,基于主成分分析、相关性分析和Norm值计算,对土壤养分、孔隙、水分、容重4类9项土壤属性指标进行筛选,构建土壤质量评价最小数据集。结果表明：(1)治理模式对土壤理化性质具有明显影响,硝态氮属于极敏感指标,全氮为高度敏感指标,而有机质、全磷、无机磷、田间持水量与饱和含水量属中度敏感指标,土壤容重为低度敏感指标;(2)影响沂蒙山区土壤质量的最小数据集指标包括全氮、土壤孔隙度、容重,经总数据集验证所构建的最小数据集可体现沂蒙山区土壤质量有效信息、准确性较高;(3)沂蒙山区不同治理模式下土壤质量指数介于0.41～0.53,土壤质量属于中等水平,且0—5 cm和5—10 cm土层的土壤质量指数较10—20 cm分别增加136.20%和37.60%。土壤质量表现为乔草混交>土坎梯田+果树种植>撂荒>封禁植草。综上,在水土流失严重、土壤较为贫瘠的沂蒙山区,生态恢复...     

基于生态系统服务价值评价的忻州市生态安全格局构建

[目的]准确识别生态保护的重要节点和区域,进而合理布局及建设生态廊道,维护生态系统可持续发展。[方法]以忻州市为例,基于生态源地-阻力面-生态网络的生态安全格局构建方法,通过生态系统服务价值评价及形态学空间学格局分析方法(MSPA)识别生态源地;基于熵权法和多阻力因子构建阻力面;运用电路理论模拟分析生态廊道和生态节点,确定生态修复的一些关键区域。[结果](1)研究区内含有生态源地59处,总面积为2 355 km²,呈现出东部集中,中西部分散的空间分布格局。(2)研究区共有生态廊道100条左右(总长度为1 637.58 km),生态夹点111处(总面积为3.16 km²)以及生态障碍点83处(总面积为48.7 km²),生态廊道按其重要程度呈现自内向外的环形分布,而生态夹点则主要散布在生态源区和廊道相互毗邻的区域。[结论]生态安全格局能够有效识别生态廊道以及生态修复的重要区域。在生态保护与恢复中,应将“保护廊道、修复夹点区域、剔除和完善障碍区域”作为总体治理策略。     

鸡新城疫、传染性支气管炎、减蛋综合征三联灭活疫苗最小免疫剂量的研究

采用北京市农林科学院畜牧兽医研究所制备的ND-IB-EDS三联灭活疫苗,分别以0.1,02,0.3,0.5mL/只的剂量免疫3周龄SPF鸡,免后3周测定ND及EDSHI抗体,然后用NDV强毒北京株攻毒;另外,首免用H120活苗免疫SPF鸡,二免分别用0.1～05mL/只三联苗,并测定2次免疫后IBHI抗体.试验结果表明,0.1 mL/只的免疫剂量就可产生较好的免疫效果,因此,确定该疫苗的最小免疫剂量为0.1 mL/只.     

基于MSPA模型和生态保护重要性评价的市域生态空间网络构建及优化

[目的] 探索基于形态学空间格局分析(MSPA)和生态保护重要性评价的市域生态网络构建方法,为市域生态网络规划与建设提供科学参考。[方法] 以黑龙江省牡丹江市为例,采用MSPA分析结果拓扑叠加研究区生态保护重要性评价,综合得出生态源地;利用最小阻力模型提取研究区潜在生态廊道并结合重力模型进行重要度划分;从源地补充、廊道补充、增补踏脚石三方面进行生态网络结构优化。[结果] ①根据MSPA分析结果,牡丹江市核心区域面积在景观类型中比例最高,为87.41%,其中林地为主要景观类型。②牡丹江市域内有主要生态源地10处,次要生态源地6处。③牡丹江市域内潜在重要生态廊道16条,一般生态廊道104条。④优化前生态网络闭合度(α指数)为0.53,优化后为0.66;网络连接数(γ指数)优化前为0.69,优化后为0.77,线点率(β指数)优化前为2.0,优化后为2.26。[结论] 综合MSPA分析法和生态保护重要性评价法的生态网络构建方法运用,有助于生态网络的结构性和功能性提升。     

基于ArcEngine的森林资源小班编辑功能的探讨

森林资源小班数据编辑是森林资源数据库建立的重要工作,基于Visual Studio 2005开发平台,应用Arc-Engine9.3二次开发组件软件,针对森林资源小班数据的新建立面域、修改与编辑多边形边界,以及因不规则采伐、火烧、病虫害、泥石流、其它工程建设等因素造成的森林资源数据更新等进行了探讨,并提出了方便、快捷、智能的开发方案,从而大大提高森林资源小班面域数据编辑的效率和精度。通过研究,得到如下结论:1)提出了对相邻面域数据无缝构建的新方法,但起始结点和终止结点必须在相邻面区域内;2)提出了相邻面域公共边无缝编辑的方案,主要通过增加、删除、移动公共结点来实现,属性数据不受到任何影响;3)提出了小班面域对象发生变化的森林资源更新方案及试例,包括几何对象和属性数据的更新,从而为森林资源管理提供方便。     

伊朗东北部的农业和牧场土壤孔隙大小分布作为土壤物理质量指标

Assessment of soil quality is important for optimum production and natural resources conservation. Agricultural and pasture soil qualities of Deh-Sorkh region located at south of Mashhad, northeastern Iran were assessed using the integrated quality index (IQI) and Nemero quality index (NQI) models in combination with two datasets, i.e., total data set (TDS) and minimum data set (MDS). In this study 6 soil properties considered as MDS were selected out of 18 properties as TDS using principle component analysis. Soil samples were divided into 3 groups based on optimum ranges of 8 soil physical quality indicators. Soil samples with the most indicators at optimum range were selected as group 1 and the samples having fewer indicators at optimum range were located in groups 2 and 3. Optimum ranges of soil pore size distribution functions were also determined as soil physical quality indices based on 8 soil physical quality indicators. Pore size distribution curves of group 1 were considered as the optimum pore size functions. The results showed that relatively high organic carbon contents could improve pore size distribution. Mean comparisons of soil physical quality indicators demonstrated that mean weight diameter of wet aggregates, structural stability index, the slope of moisture retention curve at inflection point, and plant available water content in agricultural land use decreased significantly in relation to pasture land use. In addition, the results demonstrated that the studied MDS could be a suitable representative of TDS. 78% of pasture soils had the optimum pore size distribution functions, while this parameter for agricultural soils was only 13%. In general, the soils of the studied region showed high limitations for plant growth according to the studied indicators.     

不同剂型中草药抑菌水平的分析

为观察中草药提取物的体外抑菌效果,按常规法制备中草药复方A(黄芩、连翘、大黄、蒲公英)和复方B(白头翁、黄连、黄柏、秦皮)的水提取物、醇提取物,利用管碟法和试管2倍稀释法测定中草药提取物抑菌圈的大小和对大肠杆菌的最低抑菌浓度(MIC)。结果表明,2种中草药复方对大肠杆菌均有一定的抑制作用,并且醇提物的抑菌效果均优于其水煮提取物(P<0.05)。其中复方A的醇提取物和水煮提取物的MIC分别是15.625mg/mL和31.25mg/mL;复方B的醇提取物和水煮提取物的MIC分别是31.25mg/mL和62.5mg/mL。     

The effect of hypovolemia due to hemorrhage on the minimum alveolar concentration of isoflurane in the dog

OBJECTIVE: To determine the effect of hypovolemia on the minimum alveolar concentration (MAC) of isoflurane in the dog. STUDY DESIGN: Randomized, cross-over trial. ANIMAL POPULATION: Six healthy intact mixed breed female dogs weighing 18.2-29.0 kg. METHODS: Dogs were randomly assigned to determine the MAC of isoflurane in a normovolemic or hypovolemic state with a minimum of 18 days between trials. On both occasions, anesthesia was initially induced and maintained for 40 minutes with isoflurane delivered in oxygen while vascular catheters were placed in the cephalic vein and dorsal metatarsal artery. In dogs assigned to the hypovolemic group, 30 mL kg(-1) of blood was removed at 1 mL kg(-1) minute(-1) from the arterial catheter. All dogs were allowed to recover from anesthesia. Thirty minutes after the discontinuation of isoflurane, anesthesia was re-induced with isoflurane in oxygen delivered by face mask. The tracheas were intubated, and connected to an anesthetic machine with a Bain anesthetic circuit. Mechanical ventilation was instituted at a rate of 10 breaths minute(-1) with the tidal volume set to deliver 10-15 mL kg(-1). Airway gases were monitored continuously and tidal volume was adjusted to maintain an end-tidal carbon dioxide level of 35-40 mmHg (4.67-5.33 kPa). Body temperature was maintained at 37-38 degrees C (98.6-100.4 degrees F). The MAC determination was performed using an electrical stimulus applied to the toe web and MAC was defined as the mean value of end-tidal isoflurane between the concentrations at which a purposeful movement did and did not occur in response to the electrical stimulus. The MAC values were compared between groups using a Student's t-test. RESULTS: The MAC of isoflurane was significantly less in hypovolemic dogs (0.97 +/- 0.03%) compared with normovolemic dogs (1.15 +/- 0.02%) (p < 0.0079). CONCLUSIONS AND CLINICAL RELEVANCE: The MAC of isoflurane is reduced in dogs with hypovolemia resulting from hemorrhage. Veterinarians should be prepared to deliver a lower percentage of isoflurane to maintain anesthesia in hypovolemic dogs during diagnostic and therapeutic procedures.     

The effect of experimentally induced hypothyroidism on the isoflurane minimum alveolar concentration in dogs

ObjectiveTo determine the effect of experimentally induced hypothyroidism on isoflurane (ISO) minimum alveolar concentration (MAC) in dogs.Study designProspective experimental study.AnimalsEighteen adult female mongrel dogs, age 2–4 years and weighing 8.2–13.1 kg.MethodsHypothyroidism was induced in nine dogs by the intravenous administration of 1 mCi kg⁻¹ of ¹³¹Iodine. The remaining nine dogs served as controls. Dogs were studied 9–12 months after the induction of hypothyroidism. Anesthesia was induced with ISO in oxygen via a mask. The trachea was intubated, and anesthesia was maintained using ISO in oxygen using a semi-closed rebreathing circle system. The dogs were mechanically ventilated to maintain an end-tidal carbon dioxide concentration between 35 and 45 mmHg. End-tidal ISO concentrations were measured with an infrared gas analyzer. The MAC was determined in duplicate using a tail clamp technique. The mean values for the groups were compared using a two sample t-test.ResultsThe mean ± SD MAC of isoflurane in the hypothyroid and euthyroid dogs was 0.98 ± 0.31% and 1.11 ± 0.26%, respectively. The mean MAC of isoflurane in hypothyroid dogs was not significantly different from the mean MAC of isoflurane in the control dogs (p=0.3553).Conclusion and clinical relevanceThe MAC of ISO in dogs was not significantly affected by experimentally induced hypothyroidism. The dose of ISO in dogs with hypothyroidism does not need to be altered.     

蛋鸡舍冬季CO2浓度控制标准与最小通风量确定

中国现行的蛋鸡舍内CO_2浓度控制的农业行业标准为1 500 mg/m~3,主要适用于传统的刮板式清粪鸡舍。目前新建、改建鸡舍都采用传送带清粪方式,鸡舍内的相对湿度和氨气等有害气体浓度均明显减少,其冬季最小通风量和舍内CO_2浓度参数标准均有待重新研究。该文通过总结分析国内外相关学者对不同清粪方式蛋鸡舍内NH_3、CO_2浓度的测试数据,提出传送带清粪蛋鸡舍内CO_2浓度取值建议,并根据CO_2浓度平衡原理,提出该类蛋鸡舍冬季最小通风量的取值建议。结果表明:传送带清粪蛋鸡舍内CO_2浓度参数控制标准建议可取5 000 mg/m~3;蛋鸡舍冬季连续通风最小通风量为0.40~0.50 m~3/(h·kg)。该研究为中国新建、改建传送带清粪模式蛋鸡舍CO_2浓度参数标准的取值以及调控蛋鸡舍冬季通风与保温矛盾等问题提供了参考依据。