匀密度土样制备装置的研究

研制出一种新型的用于圆锥指数测定的实验室用土样制备装置并给出了该装置的操作规范与程序。该装置适用于较大范围内土壤含水量的土样制备,而且能根据试验所要求的土壤密度,获得沿整个剖面具有密度基本一致的土壤样本。用该装置实际进行了不同土壤含水量和不同土壤密度要求的土样制备,得到了满意的结果。     

绵羊食道瘘管法和人工模拟法采集的草地牧草营养成分动态的比较研究

高山草原 7、8、10月和 1月放牧绵羊食道瘘管牧草样品和人工模拟采集牧草样品无论在粗蛋白质、粗纤维、粗灰分含量 ,还是干物质消化率方面 ,2种方法所采集牧草营养成分存在较大差异。具体表现为食道瘘管样品粗蛋白质和粗灰分含量高于人工模拟样品 ,二者最大差值分别为 6 .2 2 %和11.18% ,而粗纤维含量则低于人工模拟样品 ,最大差值为 4 .80 % ,2种方法采集牧草干物质消化率食道瘘管样也高于人工模拟样 ,二者最大差值为 7.74 %。试验表明 ,人工模拟法采集牧草样本尤其在本区黄草期 (10月 )不能真正代表放牧绵羊实际食入的牧草营养成分 ,但是在草地枯草期的 1月、二者的差值有减少的趋势。在本区放牧生态研究中牧草采样应以食道瘘管法为首选。     

Temporal effects of 3 commonly used anticoagulants on hematologic and biochemical variables in blood samples from macaws and Burmese pythons

BACKGROUND: Few studies have been done to evaluate anticoagulants for use with blood samples from birds and reptiles. Heparin currently is the most commonly used anticoagulant in practice, but may adversely affect blood cell staining and quantitation. OBJECTIVE: The purpose of this study was to evaluate the effects of lithium heparin, K3-EDTA, and sodium citrate, with and without the addition of albumin, on hematologic variables in macaw (Ara sp) and python (Python molurus bivittatus) blood samples. METHODS: Blood samples from 10 macaws and 10 Burmese pythons were collected in heparin-coated syringes and placed into tubes containing either lithium heparin, K3-EDTA, or sodium citrate with and without the addition of 0.25 mL of a 22% bovine serum albumin solution. Cell lysis was determined by counting the number of lysed cells/200 WBCs in Wright's-Giemsa-stained blood smears and by qualitative evaluation of pink plasma in microhematocrit tubes. A CBC was done after 3, 12, and 24 hours of storage at 4 degrees C in anticoagulant-containing tubes and results were compared with those obtained at 0 hour for the heparin-coated syringe sample. A biochemical panel also was done at each time point in similarly stored lithium-heparin samples. RESULTS: Hemolysis was significantly increased in citrated samples from both macaws and pythons beginning at 12 hours. At 24 hours, 19 of 30 (63%) macaw samples in all anticoagulants had >100 lysed cells/200 WBCs. There were no significant differences in hematologic values in samples from pythons collected in heparin or EDTA at any time point. No significant differences were found in the number of lysed cells or in other hematologic data in samples with albumin. Glucose concentration decreased and potassium concentration increased significantly over time in heparinized blood samples. CONCLUSIONS: Based on the results of this study, whole blood samples anticoagulated with lithium heparin or EDTA should be evaluated within 12 hours (macaws) or 24 hours (pythons) of collection and stored at 4 degrees C for best results. Citrate should be avoided as it may result in increased cell lysis. The addition of albumin does not prevent cell lysis.     

油松毛虫卵（块）和蛹种群简单随机抽样最适样方大小的确定方法

在种群空间格局的研究的基础上，采用７种方法对同松毛虫卵（块）和蛹种群简单随机抽样技术中最适样方大小的确定问题进行了研究，结果表明，无论是卵（块）抑或蛹种群，都是在ｕ＝１时抽样误差最低，即以单株油松为样方时最为适宜，此外，文中还列出了考虑抽样花费时确定最适样方式大小的各种方法，并讨论了有关问题。     

Plasma endotoxin concentration in horses: a methods study

Background: Accurate determination of plasma endotoxin concentration is critical for ex vivo and in vitro cellular and molecular studies of endotoxemia in horses. However, reports are conflicting with respect to anticoagulant, handling, and sample preparation.

Objective:

Objective: The purpose of this study was to determine the effect of blood sample fraction and handling time on measurement of endotoxin concentration in horses.

Methods:

Methods: Whole blood, anticoagulated with 3.8% (0.12 M) sodium citrate (9:1), was collected from 5 healthy horses. Whole blood (WB), platelet-rich plasma (PRP), and platelet-poor plasma (PPP) were spiked with endotoxin (2 EU/mL). Endotoxin-spiked WB samples were centrifuged immediately to generate PRP for measurement. Endotoxin concentration was subsequently measured by Limulus amebocyte assay at 0, 15, 30, 45, and 60 minutes. Assays were performed in triplicate and results were analyzed using Student's t -test, with significance set at P < .05.

Results:

Results: Mean endotoxin concentrations in 2 EU/mL-spiked WB were significantly different from those in PPP at all time points tested. Recovery of endotoxin in PRP generated from WB was significantly diminished after just 15 minutes.

Conclusion:

Conclusion: PRP generated from WB is significantly more reliable than PPP in determining endotoxin concentration ex vivo. Measurement of endotoxin in PRP generated from WB was significantly diminished after 15 min, identifying a time frame within which to process blood samples for endotoxin analysis.     

苯噻酰草胺农药标准品的制备研究

研究了苯噻酰草胺标准物质的提纯、纯化产品的定值以及定性鉴定方法。结果表明:用该法纯化的苯噻酰草胺标样纯度与国外进口标样相近,能够作为商检以及残留分析用的标准物质。     

农产品中基质对酶联免疫分析法检测三唑磷残留的干扰及消除研究

基质干扰是免疫法检测食品中农药残留时经常碰到的问题。以胡萝卜、菠菜、香蕉、梨、稻米和花生等为试材,研究了不同农产品基质对酶联免疫分析法(ELISA)检测三唑磷的影响。结果表明:不同农产品基质对ELISA检测的干扰机制不同,香蕉主要是抑制了辣根过氧化物酶的活性,菠菜、梨和稻米则主要是干扰了抗原和抗体的结合反应,胡萝卜和花生不仅抑制酶的活性,同时还干扰了抗原和抗体的结合反应。将这些农产品的磷酸盐缓冲液(PBS)(含2.5%甲醇)提取液用含有质量分数为0.3%的脱脂奶粉、0.1%的乙二胺四乙酸(EDTA)和含2.5%甲醇的PBS稀释10倍,在12000r/min下离心10min,即可消除其对ELISA检测的干扰。研究结果表明, ELISA法是可用于农产品中三唑磷残留检测的一种简单、快速、有效的方法。     

高精度保证下的浙江省森林植被生物量评估

为准确评估浙江省森林植被生物量,以2009年浙江省森林资源连续清查第一手野外调查数据为数据源,以样地为评估基本单元,采用单株生物量模型法(乔木,毛竹Phyllostachys edulis,杂竹,下木和灌木),单位面积生物量模型法(草本)和单位面积生物量法(矮化乔木林、灌木经济林),测算了样地水平的森林植被生物量.在此基础上,运用系统抽样统计方法,将样地水平微观数据转换到全省宏观尺度,评估了全省总体的森林植被生物量,提供了主要评估结果的估计精度和估计区间.结果显示:2009年,浙江省森林植被总生物量为37 010.732×104t.主要森林植被类型中,乔木林群落为29 096.269×104t,竹林群落3 762.964×104t,灌木林群落1 747.953×104t.在P＜0.05的可靠性保证下,森林植被总生物量估计精度为96.64％,估计区间为35 767.171×104～38 254.293×104t;乔木林群落9558％,估计区间为27 810.214×104～30 382324×1 04t;竹林群落89.13％,估计区间为3 353.930×104～4 171.998×104t;灌木林群落90.00％,估计区间为1 573.158×104～1 922.748×104t.可见,采用以上方法测算的浙江省各类森林植被生物量评估结果,均有很高的精度保证和较好可信度.     

底泥中多环芳烃的测定

介绍运用微波萃取提取底泥中多环芳烃的技术,在优化的试验条件下,采用气象色谱—质谱法测定底泥中的16种多环芳烃,运用加标回收率验证试验方法的可行性。结果表明:采用微波消解和硅胶净化柱对样品进行前处理,方法简便,安全,样品量大,耗时短,节省溶剂,污染小,样品加标回收率为67.353%～101.666%,效果较为理想。     

Employing a Monte Carlo algorithm in expectation maximization restricted maximum likelihood estimation of the linear mixed model

Multiple‐trait and random regression models have multiplied the number of equations needed for the estimation of variance components. To avoid inversion or decomposition of a large coefficient matrix, we propose estimation of variance components by Monte Carlo expectation maximization restricted maximum likelihood (MC EM REML) for multiple‐trait linear mixed models. Implementation is based on full‐model sampling for calculating the prediction error variances required for EM REML. Performance of the analytical and the MC EM REML algorithm was compared using a simulated and a field data set. For field data, results from both algorithms corresponded well even with one MC sample within an MC EM REML round. The magnitude of the standard errors of estimated prediction error variances depended on the formula used to calculate them and on the MC sample size within an MC EM REML round. Sampling variation in MC EM REML did not impair the convergence behaviour of the solutions compared with analytical EM REML analysis. A convergence criterion that takes into account the sampling variation was developed to monitor convergence for the MC EM REML algorithm. For the field data set, MC EM REML proved far superior to analytical EM REML both in computing time and in memory need.