Relationship of Icelandic cattle with Northern and Western European cattle breeds,admixture and population structure     

Egill Gautason  Anna A. Schönherz  Goutam Sahana  Bernt Guldbrandtsen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2020,69(1-2):25-38

ABSTRACT

Icelandic cattle is believed to have been brought from Norway during the settlement of Iceland around AD 870-930. Previous research on genetic relationships has indicated that Icelandic cattle is most related to northern Nordic indigenous breeds. Using single nucleotide polymorphism genotype data from Icelandic cattle and 29 Northern and Western European cattle breeds, we studied relationships and admixture among these breeds, and assessed population structure in Icelandic cattle. Population structure analysis through principal component analysis, estimation of ancestry, and analysis of patterns of population splitting and mixing revealed that Icelandic cattle are most related to three Finncattle breeds (Eastern, Northern and Western Finncattle), and Swedish Mountain cattle. Icelandic cattle has very low levels of admixture. We observed very limited population structure in Icelandic cattle. The observed structure was due to variable sire contributions. Over 1000 years of almost complete isolation has made Icelandic cattle highly genetically distinct from other cattle breeds.  相似文献   

The research in processing fMRI data using temporal-spatial model based on CCA     

XIAO Ke  SU Min  WU Fei 《保鲜与加工》2006,(5):124-127

In the analysis of cognition of human brain,the fMRI is often used.Corelation is a common method in fMRI data detecting,but its ability should be improved.Based on the Canonical Correlation Analysis(CCA),the temporal correlation and spatial correlation are used together to detect the activated area in the fMRI data.By the application of the method in simulation data and fMRI data,it shows that this method is effective in the detecting.  相似文献   

基于C8051F单片机的发动机转速测量   总被引：2，自引：0，他引：2  

曲金玉  任桂周  侯树展  刘大权 《拖拉机与农用运输车》2007,34(6):66-67

介绍了一种基于C8051F单片机的发动机转速实时测量方法,给出了测量系统的实现技术和硬件结构,并进行了软件设计及实验。该方法在实际测量中取得了良好的效果,为发动机动力性能研究提供了重要的参考依据。  相似文献   

稻米中同位素与多元素特征及其产地溯源PCA-LDA判别   总被引：2，自引：0，他引：2  

邵圣枝  陈元林  张永志  胡桂仙  朱加虹  袁玉伟 《核农学报》2015,29(1):119-127

通过探究谷物中同位素与多元素的地域特色及其产地溯源的可能性,本研究采用稳定同位素质谱和等离子发射光谱质谱法测定稻米中同位素比率和多元素含量,并结合化学计量学中主成分分析(PCA)和线性判别分析(LDA)法建立模型,对不同省份的稻米进行产地溯源判定。结果表明,各地产的稻米中稳定同位素δ15N、δ13C、δD、δ18O数值范围不同,而且Li、Be和Na等其他矿物元素的含量变化较大,Pb、Sr同位素比率也各不相同,具有一定的地域特征。PCA法能够初步辨别各稻米地产,本研究进一步采用PCA-LDA法能够对大区域(黑龙江省、江苏省和辽宁省)的稻米进行产地判别,通过对23个样本进行判别验证,正确率为91%。对于黑龙江省4个地产的稻米样品,由于地理差异性比较小,同时样本数比较少,故只对其中2个产地稻米进行判别。通过同位素比率和多元素的含量的测定再结合化学计量学分析,一定程度上能够区分不同产地的稻米,为稻米产地溯源的可行性提供了方法依据。  相似文献   

四川省长江上游水土保持工程生态经济综合评价   总被引：3，自引：2，他引：3  

邓欧  尹忠东  冯仲科  李亦秋  张冬有 《农业工程学报》2010,26(5):88-95

小流域水土流失治理策略及其生态经济评价是水土保持学科的热点问题,以整个工程实施范围作为对象的研究成果鲜见报道。该文以四川省长江上游水土保持重点防治综合治理第五期工程整个治理区域为研究对象,以县级行政区内的小流域综合治理区域为评价单元,选取反映项目区社会经济和生态状况的46个指标,通过运用主成分分析法和多元线性回归分析,得出13种治理措施主成分,并对治理前后的生态经济状况进行综合评价和排序,建立了生态经济综合发展水平位次变化与治理措施主成分之间的多元线性回归模型。结果表明：不同的治理措施、治理措施实施的范围大小、实施的力度和强度是影响其对于生态经济发展水平贡献大小的主要原因。  相似文献   

引入因素分析法的神经网络在洪水     

梅松  程伟平  刘国华 《中国农村水利水电》2005,(7):13-16

因素分析法是一种多元统计法，可以通过线性变换，将原有数据转换成彼此不相关且维数较少的数据，本文将因素分析法引入洪水预报神经网络的输入单元精简过程，详细介绍了建模和神经网络训练过程中包括STA训练控制在内的一些关键技术问题，并通过实例评价了此应用方法的效果，通过分析，表明此方法可以在不损失或较小损失的前提下方便有效的对洪水预报神经网络结构进行精简，大大缩减了神经网络的规模，提高了效率，具有很高的实用价值。  相似文献   

Cultivation effects on soil texture and fertility in an arid desert region of northwestern China     

Mingzhu HE 《干旱区科学》2020,12(4):701-715

In arid desert regions of northwestern China, reclamation and subsequent irrigated cultivation have become effective ways to prevent desertification, expand arable croplands, and develop sustainable agricultural production. Improvement in soil texture and fertility is crucial to high soil quality and stable crop yield. However, knowledge on the long-term effects of the conversion of desert lands into arable croplands is very limited. To address this problem, we conducted this study in an arid desert region of northwestern China to understand the changes in soil physical-chemical properties after 0, 2, 5, 10, 17, and 24 years of cultivation. Our results showed that silt and clay contents at the 17-year-old sites increased 17.5 and 152.3 folds, respectively, compared with that at the 0-year-old sites. The soil aggregate size fraction and its stability exhibited an exponential growth trend with increasing cultivation ages, but no significant change was found for the proportion of soil macroaggregates (>5.00 mm) during the 17 years of cultivation. The soil organic carbon (SOC) content at the 24-year-old sites was 6.86 g/kg and increased 8.8 folds compared with that at the 0-year-old sites. The total (or available) nitrogen, phosphorus, and potassium contents showed significant increasing trends and reached higher values after 17 (or 24) years of cultivation. Changes in soil physical-chemical properties successively experienced slow, rapid, and stable development stages, but some key properties (such as soil aggregate stability and SOC) were still too low to meet the sustainable agricultural production. The results of this long-term study indicated that reasonable agricultural management, such as expanding no-tillage land area, returning straw to the fields, applying organic fertilizer, reducing chemical fertilizer application, and carrying out soil testing for formula fertilization, is urgently needed in arid desert regions.  相似文献   

Sargassum horneri as a Functional Food Ameliorated IgE/BSA-Induced Mast Cell Activation and Passive Cutaneous Anaphylaxis in Mice     

Eui Jeong Han  Hyun-Soo Kim  Kalu Kapuge Asanka Sanjeewa  Kyungsook Jung  Youngheun Jee  You-Jin Jeon  Ilekuttige Priyan Shanura Fernando  Ginnae Ahn 《Marine drugs》2020,18(12)

Sargassum horneri (S. horneri), an edible brown alga, has been proposed as a functional food with an improvement effect on abnormal skin immune responses. The present study investigates the anti-allergic effect of an ethanol extract from S. horneri (SHE) on immunoglobulin E (IgE)/bovine serum albumin (BSA)-mediated activation in bone marrow-derived cultured-mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) reaction in mice. SHE markedly and dose-dependently suppressed the degranulation of BMCMCs by reducing the β-hexosaminidase and histamine release without cytotoxicity. In addition, SHE significantly decreased the FcεRI expression on the surface of BMCMCs and its IgE binding. Moreover, SHE reduced the mRNA expression and the production of allergic cytokines; interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-10, IL-13; interferon (IFN)-γ and/or tumor necrosis factor (TNF)-α; and a chemokine, thymus and activation-regulated chemokine (TARC), by suppressing the activation of Src-family kinases and nuclear factor (NF)-κB signaling. In further study, the application of SHE reduced the PCA reaction in an IgE/BSA-induced type I allergic mice model. Taken together, we suggest that SHE has an anti-allergic effect in type I allergic responses.  相似文献   

基于非线性主成分分析法的区域物流发展综合评价模型   总被引：13，自引：1，他引：13  

王振锋  王淮东  徐广印  王巍  曲建华  梁广华 《河南农业大学学报》2006,40(5):545-548,552

利用非线性主成分分析法对河南各地区的物流发展状况进行分析,将得到的综合主成分指标代替原来较多的评价指标建立模型,对河南各个地区的物流发展综合实力进行评价.结果表明,该方法能够把复杂的问题简化,所得结论科学客观、可信.  相似文献   

基于近红外漫反射光谱的规模化奶牛场粪水氮磷定量分析及模型构建   总被引：2，自引：2，他引：2  

赵润  牟美睿  王鹏  孙迪  刘海学  张克强  杨仁杰 《农业环境科学学报》2019,38(8):1768-1776

为建立规模化奶牛场粪水中氮磷含量现场快速检测方法,以实现准确预测的同时替代常规监测程序,选取23家天津市典型种养结合模式的规模化奶牛场,围绕粪水处理全过程环节依次开展样品采集、实验室常规化学检测、近红外漫反射光谱采集,并进行主成分分析和偏最小二乘分析,建立多种动态复合影响因素条件下的全局、全程快速检测定量分析模型。结果表明:主成分分析不仅反映出同一奶牛场粪水有机组分随处理环节的变化,而且也反映出不同奶牛场粪水样品的差异性,以及在粪水处理过程中各因素对后续模型的影响程度。建立的全过程环节定量分析模型对总氮含量预测结果与实际含量的线性拟合相关系数R为0.96,预测均方根误差RMSEP为187.80;对总磷含量预测结果与实际含量的线性拟合相关系数R为0.91,预测均方根误差RMSEP为3.59。建立的全局定量分析模型对总氮含量预测结果与实际含量的线性拟合相关系数R为0.96,预测均方根误差RMSEP为238.59;总磷含量预测结果与实际含量的线性拟合相关系数R为0.91,预测均方根误差RMSEP为6.56。研究表明,基于近红外漫反射光谱和偏最小二乘法对规模化奶牛场粪水处理全过程环节粪水样品中氮、磷含量进行定量分析是可行的;纵向模型比横向模型能提供更好的预测结果;近红外漫反射光谱技术可实时、快速、高效地对规模化奶牛场粪水处理全过程总氮和总磷进行跟踪和监控。  相似文献