A new method of searching for concealed Au deposits by using the spectrum of arid desert plant species

With the increase of exploration depth, it is more and more difficult to find Au deposits. Due to the limitation of time and cost, traditional geological exploration methods are becoming increasingly difficult to be effectively applied. Thus, new methods and ideas are urgently needed. This study assessed the feasibility and effectiveness of using hyperspectral technology to prospect for hidden Au deposits. For this purpose, 48 plant (Seriphidium terrae-albae) and soil (aeolian gravel desert soil) samples were first collected along a sampling line that traverses an Au mineralization alteration zone (Aketasi mining region in an arid region of China) and were used to obtain soil Au contents by a chemical analysis method and the reflectance spectra of plants obtained with an Analytical Spectral Device (ASD) FieldSpec3 spectrometer. Then, the corresponding relationship between the soil Au content anomaly and concealed Au deposits was investigated. Additionally, the characteristic bands were selected from plant spectra using four different methods, namely, genetic algorithm (GA), stepwise regression analysis (STE), competitive adaptive reweighted sampling (CARS), and correlation coefficient method (CC), and were then input into the partial least squares (PLS) method to construct a model for estimating the soil Au content. Finally, the quantitative relationship between the soil Au content and the 15 different plant transformation spectra was established using the PLS method. The results were compared with those of a model based on the full spectrum. The results obtained in this study indicate that the location of concealed Au deposits can be predicted based on soil geochemical anomaly information, and it is feasible and effective to use the full plant spectrum and PLS method to estimate the Au content in the soil. The cross-validated coefficient of determination (R²) and the ratio of the performance to deviation (RPD) between the predicted value and the measured value reached the maximum of 0.8218 and 2.37, respectively, with a minimum value of 6.56 μg/kg for the root-mean-squared error (RMSE) in the full spectrum model. However, in the process of modeling, it is crucial to select the appropriate transformation spectrum as the input parameter for the PLS method. Compared with the GA, STE, and CC methods, CARS was the superior characteristic band screening method based on the accuracy and complexity of the model. When modeling with characteristic bands, the highest accuracy, R² of 0.8016, RMSE of 7.07 μg/kg, and RPD of 2.20 were obtained when 56 characteristic bands were selected from the transformed spectra (1/lnR)' (where it represents the first derivative of the reciprocal of the logarithmic spectrum) of sampled plants using the CARS method and were input into the PLS method to construct an inversion model of the Au content in the soil. Thus, characteristic bands can replace the full spectrum when constructing a model for estimating the soil Au content. Finally, this study proposes a method of using plant spectra to find concealed Au deposits, which may have promising application prospects because of its simplicity and rapidity.     

不同层积处理对核桃种子发芽的影响

为了明确层积催芽时间对核桃发芽率的影响,以云新14#为研究对象进行了分析。结果表明,经过GA3150mg·L-1浸种8d后并进行层积35d种子萌动率最高,达到了82%;GA3150mg.L-1浸种催芽35d发芽情况最好,发芽率达到了94%,烂种率为6%,好种率为0。在生产中建议核桃层积催芽时间35d为宜。     

欧洲黑杨优质核心种质库的初步构建

对159份欧洲黑杨种质资源的生长、育种值、材性、养分利用率和水分利用率等13个性状进行分析,采用13种表型选优的抽样方法构建欧洲黑杨优质核心种质库。表型值评价表明：当抽样群体比例达到21.4%以上即能满足构建核心种质要求,而只有抽样群体比例达到30.2%以上 SSR 分子遗传多样性才能满足构建核心种质要求。最终确定的欧洲黑杨优质核心种质库包含48份种质资源,占原群体的30.2%;与原群体相比,均值和方差不存在显著差异,极差符合率和变异系数变化率分别为97.07%和89.72%;优质核心种质库的有效等位基因数、Nei’s 遗传多样性系数和 Shannon’s 信息指数与原群体之间没有显著差异,保持了原群体的遗传多样性。     

辣椒SRAP-PCR反应体系优化及杂交群体多态性引物筛选

[目的]对辣椒SRAP反应体系进行研究和优化,并利用优化体系对164对多态性引物进行筛选。[方法]采用单因素随机试验设计和L25(65)正交试验设计对辣椒SRAP反应体系中6种关键因素(退火温度、Taq DNA聚合酶、Mg2+、dNTPs、引物、模板DNA)进行体系优化,并以"泡椒"×"青皮大椒"的亲本和F1代为材料,利用聚丙烯胺酰胺凝胶进行筛选。[结果]辣椒SRAP-PCR的最佳反应体系为:退火温度35.5℃,Taq DNA聚合酶1.0 U,模板DNA 2.25 ng/μl,dNTPs 0.2 mmol/L,引物0.4μmoL/L,Mg2+2 mmol/L,总体积为20μl。利用该体系,从164对SRAP引物组合中筛选出扩增条带清晰、多态性丰富、条带稳定的31对引物组合。[结论]该体系的建立与多态性引物组合的筛选为SRAP标记技术在辣椒育种中的应用奠定了基础。     

南北五味子随机扩增DNA多态性（RAPD）指纹图谱研究

目的建立南北五味子随机扩增DNA多态性标记（（random amplified polymorphic DNA,RAPD）指纹图谱,为南北五味子的鉴别提供可靠依据．方法采用CTAB法从不同产地的南北五味子样品中提取基因组DNA并纯化,将南北五味子基因组DNA进行随机DNA多态性扩增．结果北五味子和南五味子基因组DNA随机引物PCR扩增产物的差异以不同条带数目和条带亮度得已验证;同时体现出北五味子种内变异较小,南五味子种内变异较大．结论RAPD技术为南、北五味子的鉴别提供一种简单、有效、可信度高的方法．     

蔬菜质量分级和销售渠道拓展对 菜农收益的影响研究

农业是我国的基础产业,蔬菜作为农产品的一个必要组成部分,其发展水平对农民生活生产有重要影响。蔬菜品质区别大而且供给链较长,且蔬菜的市场价格时高时低,这种不稳定性使菜农的蔬菜出售价格不高,对菜农有不利影响。因此,在我国现有的市场条件下,寻找一种保障菜农基本利润的措施以提高菜农的收益是很有必要的。通过理论推导,得出了蔬菜质量分级和销售渠道拓展能够有效提高菜农的利润,提出了相应的政策建议。     

海巴戟核心种质的构建方法

以126份海巴戟种质资源为材料,利用生物学性状、农艺学性状、SRAP分子标记等遗传多样性数据,采用逐步聚类法,开展海巴戟核心种质构建机制的研究。结果表明:海巴戟核心种质的最佳构建方法为Average系统聚类,G策略取样,15%的组内取样比例。应用该构建方法初步构建了由21个不同种质株系构成的海巴戟核心种质,该核心种质能够代表原种质的遗传多样性。     

Faecal Sampling Underestimates the Actual Prevalence of Salmonella in Laying Hen Flocks

Summary In all European Union member states, Salmonella monitoring in poultry flocks is obligatory. In these monitoring programmes, a limited number of pooled faeces and/or dust samples are collected to determine whether Salmonella is present in the flocks or not. Whether these limited sampling protocols are sufficiently sensitive to detect expected low within‐flock prevalences of an intermittently shed pathogen is not yet clear. In this study, a comparison is made between different sampling procedures for the assessment of the between‐ and within‐flock prevalence of Salmonella in laying hens. In total, 19 farms were sampled. Using a comparable sampling methodology as in the official surveillance programmes, Salmonella could not be detected in any of the flocks. After transportation of the hens to the laboratory and subsequent analysis of cloacal swabs and caecal contents, Salmonella Enteritidis was detected in laying hens from five of 19 farms. The observed within‐flock prevalence ranged from 1% to 14%. Based on the results of this study, it can be expected that, depending on the sampling procedure, different estimates of the prevalence of Salmonella can be obtained and the proportion of Salmonella infected flocks is underestimated based on the results of the official monitoring programme.     

利用抽样函数实现螺线聚焦管道中的束晕-混沌控制研究

根据束晕-混沌控制策略方法,利用具有非线性、收敛性的抽样函数构造控制器,对初始条件遵从K-V 分布的离子束进行了控制研究。结果表明,加控制后束晕强度因子变为零,束均方根半径、束横向动量平方和的平均值和束横向平均发射度比控制前都明显减小。利用该方法可实现束晕-混沌的有效控制。     

青海省都兰县沟里乡智玉村野生雪豹调查

采用样线法和访问调查法对位于昆仑山余脉布尔汗不达山区的青海省都兰县沟里乡智玉村地区的雪豹进行了初步调查。共设32条样线,在其中的4条样线上发现了雪豹的痕迹（足迹、刨痕、尿迹、粪团和食物残骸）,通过调查数据的取得,对该地区雪豹的种群密度做出了初步的估计,同时分析了该地区雪豹种群数量变化的原因,提出了针对雪豹保护工作的建议。