四个水稻新品种在海南澄迈早季的试种表现

对从广东引进的华新占、玉晶占、黄丝占、合美占等4个水稻品种在海南澄迈进行了试种。结果表明,玉晶占产量最高、综合性状好,产量为524.0kg/667m2,比对照海秀占9号增产16.44%;其次是华新占,产量为496.0kg/667m2,比对照海秀占9号增产1.02%;黄丝占、合美占在产量、米质、抗病性等方面的表现一般,在海南澄迈早季没有种植优势。     

Sequential sampling plans for estimating density of glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae) on citrus

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is a serious pest of grapes and other crop and ornamental plants mainly through its role as a vector of the bacterium Xylella fastidiosa Wells. Citrus harbors large populations of this insect throughout much of the year in areas where the pest is problematic and improved understanding of the population dynamics and management of H. vitripennis on citrus may be key to its management in the broader agricultural landscape. In turn, the study of population dynamics and the development of management strategies require effective and efficient sampling methods. Within-tree sampling distribution studies revealed that adults and nymphs were more abundant and less variable in the upper strata of citrus trees (>1.5 m). They occurred in greater numbers on the southern quadrants of trees but relative variability did not differ due to cardinal direction. We developed and validated several fixed-precision sequential sampling plans for estimating the density of nymphs and adults of H. vitripennis using a pole bucket sampling method. Based on validation from resampling of independent data sets, Green’s sequential sampling model, based on the Taylor’s power law, provided the best overall performance in terms of providing mean density estimates with levels of precision equal to or better than the desired precision over a range of possible insect densities. Average sampling costs varied from about 21 to 189 min for a desired precision of 0.25 depending on insect density and whether the goal is to sample nymphs, adults or both stages combined. Further, the sampling plans developed on orange trees were robust, being equally effective on orange and lemon trees and on trees treated or not with insecticides.     

Parameter optimized Morlet wavelet de noising method based on cross validation method

A new de noising method based on parameter optimized Morlet wavelet is put forward. The Morlet wavelet is chosen as the mother wavelet because its shape is similar to the mechanical shock signals. The mother Morlet wavelet is improved by adding two parameters which decide the shape of the mother wavelet in time domain. The added parameters and the appropriate scale parameter for the wavelet transformation are designed by the cross validation method. Finally, the useful components of the signal can be obtained by the improved Morlet wavelet de noising method. The gear fault diagnosis experimental result shows that the proposed method has a good de nosing performance and it is effective in fault feature extraction.     

前弯型叶片液力透平的数值计算

为研究具有前弯型叶片液力透平的性能,设计了3种不同比转数具有前弯型叶片液力透平.采用全流场和结构化网格技术对液力透平内部流动进行数值计算,分析了具有前弯型叶片液力透平在不同流量下的外特性、压力场和速度场,得到了液力透平叶轮和尾水管内部流场随流量变化规律.研究结果表明:透平内部压力场从蜗壳进口经叶轮到尾水管出口压力逐渐减小,随流量的增大,液力透平的进出口压差逐渐增大;在前弯型叶片工作面存在旋涡区域,旋涡位置和区域大小随着流量的变化而变化;在尾水管横截面上存在随流量而变化的圆周速度分量;叶轮内部的水力损失是前弯型叶片液力透平内部的主要的水力损失,在3种液力透平中都占总水力损失的60%以上,并随比转数增大而逐渐增大.因此,前弯型叶片液力透平的优化设计应主要集中在叶轮研究.     

新疆天山山区TRMM卫星降水数据的精度检验和校正方法研究

在降水资料缺乏的天山山区,基于重建时间序列后的NDVI和DEM数据,采用CART算法对TRMM3B43月降水数据进行校正。利用研究区25个站点实测降水量对校正前的TRMM降水数据和校正后的TRMM降水数据分别进行精度检验。结果表明:校正前TRMM月降水与站点实测降水有很好的一致性,存在显著的线性相关关系,但误差较大;TRMM降水与实测降水的决定系数(R2)随时间尺度的增大而减小,相对误差(δ)和均方根误差(RMSE)则随之增大,说明TRMM遥感数据的精度随时间尺度的增加而减小;校正后TRMM降水精度得到了显著地提高,与实测降水在月、季、年尺度上的R2分别为:0.97,0.87,0.83,相比校正前R~2提高了10%以上,误差也有明显的减小。这说明在天山山区,使用CART对TRMM降水数据进行校正的方法可行。     

Validation of Microbial Limit Test Method for Traditional Chinese Medicine Dichroa febrifuga Oral Liquid (DFOL)

The purpose of this study was to validate the microbial limit test method for anticoccidial drug Dichroa febrifuga oral liquid (DFOL),and provide data base for its quality control and researching the new veterinary drug. The direct inoculation method was used to validate the antibacterial activity for DFOL, and the bacterial counting,determination of recovery rate and inspection of control bacteria were measured using a validated test condition and method (conventional method).The results showed that DFOL had no or faint bacteriostasis verified by validated test method, the determination and inspection of bacteria could be determined by conventional method. The normal plate counting were used to detect the amount of Escherichia coli,Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger in DFOL in which the recovery rate were all more than 70%,and the results were not disturbed by sample and diluents. The control bacteria including Escherichia coli,Salmonella paratyphi B,Staphylococcus aureus,and Pseudomonas aeruginosa were tested according to conventional method,whose growth were detected in the test group and positive control group, while no growth were detected in the negative control group and sample group. In conclusion,the microbial limit test method for DFOL had been validated in this study,and the conventional method could be applied to DFOL for bacteria,moulds and yeast counting as well as the inspection for control bacteria. The process of test was in accordance with the regulations of microbial limits test method,the method was convenient and simple,and the results was reliable.     

Calibration of pesticide leaching models: critical review and guidance for reporting

Calibration of pesticide leaching models may be undertaken to evaluate the ability of models to simulate experimental data, to assist in their parameterisation where values for input parameters are difficult to determine experimentally, to determine values for specific model inputs (e.g. sorption and degradation parameters) and to allow extrapolations to be carried out. Although calibration of leaching models is a critical phase in the assessment of pesticide exposure, lack of guidance means that calibration procedures default to the modeller. This may result in different calibration and extrapolation results for different individuals depending on the procedures used, and thus may influence decisions regarding the placement of crop-protection products on the market. A number of issues are discussed in this paper including data requirements and assessment of data quality, the selection of a model and parameters for performing calibration, the use of automated calibration techniques as opposed to more traditional trial-and-error approaches, difficulties in the comparison of simulated and measured data, differences in calibration procedures, and the assessment of parameter values derived by calibration. Guidelines for the reporting of calibration activities within the scope of pesticide registration are proposed.     

Validation of the Nova CRT8 for the measurement of ionized magnesium in feline serum

Background: Evaluation of serum magnesium (Mg) concentration is becoming important in human and veterinary critical care medicine. An ion‐selective electrode can measure the physiologically active ionized fraction. Objectives: The purpose of this study was to validate an ion‐specific electrode analyzer and assay for measuring ionized Mg in feline serum and to determine a reference interval for this analyte in cats. Methods: Venous blood samples were collected anaerobically from clinically healthy cats, and the serum was used to validate the analyzer and assay. This included investigating the stability of samples stored at different temperatures, intra‐ and interassay precision, linearity, analytical sensitivity, and potential interferences from bilirubin, lipemia, hemoglobin, or serum separator tubes. A reference interval was calculated. Results: Serum samples evaluated for ionized Mg concentrations can be stored at 20°C for ≤24 hours, at 4°C for ≤72 hours, and at ?20°C for ≤4 weeks, when samples are minimally exposed to air. Intra‐ and interassay precisions had coefficients of variation (CVs) of 1.23% and 2.02%, respectively. There was good linearity using serum (r= .998; y=?0.0057 + 1.0256x) and manufacturer‐supplied aqueous solutions and quality control materials (r= .999; y= 0.0110 + 0.9213x). Apparent analytical sensitivity was at least 0.015 mmol/L. Mean recovery was good for ionized Mg in samples with ≤1+ icterus (104%), 4+ lipemia (99.3%) and 1–4+ hemolysis (98.6%). There was no significant difference (P= .52) in ionized Mg concentrations in serum collected in tubes containing no additives compared with serum collected in glass separator tubes. The serum ionized Mg reference interval was 0.47–0.63 mmol/L (n = 40). Conclusions: The Nova CRT8 analyzer and assay provide a precise and reliable method of measuring ionized Mg concentration in feline serum. Strict adherence to sampling techniques, handling, and storage are necessary for reliable results.     

Modeling hydrology, metribuzin degradation and metribuzin transport in macroporous tilled and no-till silt loam soil using RZWQM

Due to the complex nature of pesticide transport, process-based models can be difficult to use. For example, pesticide transport can be effected by macropore flow, and can be further complicated by sorption, desorption and degradation occurring at different rates in different soil compartments. We have used the Root Zone Water Quality Model (RZWQM) to investigate these phenomena with field data that included two management conditions (till and no-till) and metribuzin concentrations in percolate, runoff and soil. Metribuzin degradation and transport were simulated using three pesticide sorption models available in RZWQM: (a) instantaneous equilibrium-only (EO); (b) equilibrium-kinetic (EK, includes sites with slow desorption and no degradation); (c) equilibrium-bound (EB, includes irreversibly bound sites with relatively slow degradation). Site-specific RZWQM input included water retention curves from four soil depths, saturated hydraulic conductivity from four soil depths and the metribuzin partition coefficient. The calibrated parameters were macropore radius, surface crust saturated hydraulic conductivity, kinetic parameters, irreversible binding parameters and metribuzin half-life. The results indicate that (1) simulated metribuzin persistence was more accurate using the EK (root mean square error, RMSE = 0.03 kg ha(-1)) and EB (RMSE = 0.03 kg ha(-1)) sorption models compared to the EO (RMSE = 0.08 kg ha(-1)) model because of slowing metribuzin degradation rate with time and (2) simulating macropore flow resulted in prediction of metribuzin transport in percolate over the simulation period within a factor of two of that observed using all three pesticide sorption models. Moreover, little difference in simulated daily transport was observed between the three pesticide sorption models, except that the EB model substantially under-predicted metribuzin transport in runoff and percolate >30 days after application when transported concentrations were relatively low. This suggests that when macropore flow and hydrology are accurately simulated, metribuzin transport in the field may be adequately simulated using a relatively simple, equilibrium-only pesticide model.