Fire behavior characteristics in a pine needle fuel bed in northwest Africa

This paper reports results of research to validate a fire behavior model "Wildland Fire Dynamics Simulator" through comparison of laboratory-scale measurements under the oxygen consumption calorimetry principle to several simulation runs of ground fire spreading in a fuel bed under wind. Pine needle ground covers of Pinus halepensis Mill. and Pinus pinaster Ait., two pine species in a specific region in northwest Africa were tested. In order to gain a deeper understanding of forest fire behavior, investigation into the rate of spread, one of the most relevant quantities used in forest fire science, is fundamental. Moreover, the heat release rate of the fire spread for different fuel types and related thermal functions such as radiant, convective and conductive heat transfer through beds of pine needles were quantified. The results can be helpful for the improvement and validation of the computational Fluid Dynamics CFD model and give global information on fire spread under wind on a bed of pine needles.     

Use of the management-oriented silvopastoral model ALWAYS: Calibration and evaluation

The ALWAYS model simulates the biophysical functioning of a silvopastoral plot – here the broad-leaved tree — pasture — sheep association — and its management, according to the interactions between the different components of the system. The model was calibrated for two silvopastoral plots with contrasting soil and climate: at Lamartine in central France (wet upland climate), and at Cessous in southern France (a moderate hot and dry Mediterranean climate). The actual plot management recorded in the field was used in the model (and particularly date and number of grazing animals) and the model was run for different time series (from 2 to 100 years) depending on the process we wanted to evaluate, grass and animal production or tree growth. Models outputs were consistent with recorded data on the field and we concluded that the model can correctly simulate the behaviour of a silvopastoral plot in terms of tree growth, grass production, animal grazing and interactions between the different components. It permitted also to make consistent choices and compare different strategies of silvopastoral plots management. The improvement of some biophysical processes that are very simplified in the model is required to produce better accurate predictive values of sward or tree production. But a much more complex model will require more data for its parametrization and more time to run, precluding its use in many situations.This revised version was published online in November 2005 with corrections to the Cover Date.     

Assessment of the repeatability of a milk Ostertagia ostertagi ELISA and effects of sample preparation

An indirect Ostertagia ostertagi ELISA on milk is a promising diagnostic tool in bovine parasitology. Interpretation of the test results requires a good knowledge of the test characteristics. In this study, border effects, the repeatability of the ELISA and the effect of different factors such as storage, skimming and freeze–thaw cycles of the milk samples were investigated. The border effects trial showed that significant border effects can occur. The repeatability trial was conducted over 3 days. An alternative graphical technique to assess the repeatability over a large number of ELISA plates measured over different days was developed. From these graphs, it was obvious that the ODR values obtained on the third day were deviating from the values on the first and second day. On the third day, also abnormal control values were observed. When the control values were normal, 94% of the variability was explained by the milk sample and 6% by assay variability. The expected 95% range of the difference of 2 ODR readings of the same sample on the same plate and the same sample on different plates was −0.14 to 0.14 and −0.16 to 0.16. No extra variability was observed when samples were tested on a different day, however these results are based on the measurement of 2 days. Storage for 2–4 days at 4 °C, using whole milk instead of skimmed milk and up to 2 extra freeze–thaw cycles of the milk samples did not significantly affect the test results.     

内蒙古玉米品种审（认）定现状与育种对策

文章通过对内蒙古自治区审（认）定玉米品种的地区分布、单位类型、育种方法和应用状况分析。指出内蒙古玉米品种创新、育种方法、科研机制等方面存在的主要问题,提出明确目标、加强基础研究、改进技术的育种对策,以期为玉米品种选育提供参考。     

棉花干物质积累的模拟模型与检验

建立了棉花群体光合生产和干物质积累模拟模型。其中,包括了作物叶面积动态、光能截获及光合与呼吸作用等主要生理过程,而且考虑了温度、肥料及其它绿色部分的影响。结果表明：模拟值与实测值的相关系数为０．９０４６,模拟误差为３１０．３０５ｋｇ／ｈｍ２。     

刺参(Apostichopus japonicus)重要经济性状相关SNP标记的验证分析

本研究在前期构建的刺参(Apostichopus japonicus)高密度遗传连锁图谱和QTL分析的基础上,筛选出26个与体长、体重、体宽、棘刺总数、抗病力相关的SNP位点,设计出可用于HRM检测的SNP扩增引物13对。在扩大群体中利用HRM小片段法对这13个刺参重要经济性状相关的候选SNP位点进行分型和多态性检测,并结合扩大群体的相关性状数据进行了QTL位点验证。多态性结果显示,13个位点中有3个单态性位点,其余10个多态性位点中有3个位点为低等位多态性,7个位点为中等位多态性。10个多态性位点的最小等位基因频率(MAF)介于0.016(SNP113)～0.332(SNP160)之间,平均值为0.173;各位点的观测杂合度(Ho)介于0.031(SNP113)～0.818(SNP9)之间,平均值为0.433;期望杂合度(H_o)介于0.031(SNP113)～0.834(SNP9)之间,平均值为0.402;多态信息含量(PIC)介于0.030(SNP113)～0.393(SNP160)之间,平均为0.248,有6个位点偏离HardyWeinberg平衡。QTL验证结果表明,SNP40和SNP160位点为与生长(体长、体重、体宽)相关的位点,各位点的优势基因型分别为SNP40(CC)和SNP160(AA);SNP88、SNP112和SNP126这3个位点为与抗病力相关的位点,各位点的优势基因型为SNP88(CC)、SNP112(AA)和SNP126(TT)。基于这5个位点构建生长和抗病二倍型,发现二倍型K_1(CC AA TT)抗病力最强,S_1(CC AA)、S_3(CC AC)在生长方面优势显著,相关研究结果可为分子标记辅助育种在生产中应用提供基础数据。     

First report on the presence of Alloxan in bleached flour by LC-MS/MS method

In this work the presence of Alloxan in bread, pastry and cake bleached flour was investigate in order to verify possible risk for consumers related to the use of chemicals for flour bleaching. A selective UHPLC–MS/MS method has been developed and validated for the purpose. Alloxan is one of the possible minor side products of oxidation after chemical bleaching of wheat flours, when several chemical agents are used. One hundred and seventy-five flour samples were analyzed for Alloxan determination. The validation of the method was performed in accordance with the ISO/IEC/EN 17025 for linearity, detection limit, quantification limit, accuracy, precision and ruggedness determination. Satisfactory performances were obtained for the analyte, with a Limit of Detection (LOD) of 0.73 mg kg⁻¹, a Limit of Quantification (LOQ) of 0.85 mg kg⁻¹ and recovery values between 94% and 102%. The present work report for the first time the presence of trace levels of Alloxan in 24% of the analyzed samples, with mean values of 0,95 ± 0,04 mg kg⁻¹. The presence of Alloxan was detected only in cake flour samples. Further studies on toxicological levels of Alloxan are needed in order to evaluate possible risks for consumers linked to the consumption of bakery products.     

基于WOFOST模型的华北冬小麦动态长势评估指标构建

为构建基于WOFOST作物模型主要输出要素地上部生物量(TAGP)和叶面积指数(LAI)的华北平原冬小麦长势评估指标,利用华北平原冬小麦主产区农业气象站冬小麦生育期、叶面积指数和土壤湿度等观测资料以及河北固城站、河南郑州站和山东泰安站3个农业气象试验站冬小麦生物量观测资料,完成WOFOST模型参数本地化和适应性分析。利用华北平原354个气象站2001-2016年逐日气象资料驱动模型,根据不同时段15年地上总生物量(TAGP)和叶面积指数(LAI)要素及其与15年平均值的距平百分率的概率统计分布,确定冬小麦长势动态评估指标;利用冬小麦田间观测资料,检验指标的合理性和有效性。结果表明:(1)试验站观测值与模拟值对比显示,冬小麦生育期模拟误差绝对值平均为3.7d,地上部总生物量及各器官生物量的误差为3.8%～11.7%,WOFOST模型可较为准确地模拟冬小麦生长发育及其生物量的动态累积过程,在华北平原适用性良好;(2)基于指标的动态长势评估等级与观测数据对比,2个农业气象试验站点的指标评估结果与观测资料一致性较好,1个站点的结果则在冬小麦生长过程中呈波动状态,总体上基于LAI的长势评价指标与观测资料对比相关系数高于基于TAGP的评价指标;(3)基于WOFOST模型的冬小麦长势评估指标能够一定程度反映冬小麦长势状况,可用于业务中进行实时、动态和定量的评估。     

采样点数量对长三角典型地区土壤肥力指标空间变异解析的影响

通过对江苏省如皋市888个采样点的不重复随机抽样,探讨了采样点数量对土壤肥力指标空间变异解析的影响。从半方差函数估计的可靠性角度考虑,在长江冲积物形成的土壤上,针对县级农业管理和生态环境规划的土壤肥力指标调查采样,采集250个样点较为合适。另外,仅使用交互验证和独立验证评价半方差函数估计的可靠性及确定采样点数量是不完善的,而平均克里格方差理论上随采样点数量的增加而单调递减,可以作为不同采样点数量条件下,综合评价半方差函数估计可靠性及确定采样点数量的补充指标。