基于熵权物元模型的青海省土地生态安全评价

为了科学评判生态脆弱区青海省土地资源的生态安全及其变化情况,运用熵权法和P-S-R模型,构建该区域土地生态安全评价指标体系及权重,采用物元理论建立土地生态安全的综合评判模型,并对青海省2000—2010年土地生态安全状况变化情况及空间差异进行了分析。结果表明：青海省土地生态安全的发展趋势大体表现为“较不安全→临界安全”;青海省各市（州、地区）的土地生态安全状况变化情况不尽相同,地区间差异明显;影响青海省土地生态安全水平的主要制约因素包括经济密度、人均耕地面积、林草覆盖率、水土协调度、成灾面积比重和化肥施用量。     

稠油管输起始加热温度熵产最小优化设计

基于熵产率最小化原理,分析了原油在输送过程中散热损失和摩擦阻力引起的熵产情况,优化了熵产率最小所对应的管输起始加热温度。研究结果表明:最小熵产率与输送流量、起始温度和管道管径有关,输量对熵产率有一定的影响,输量越高,输送单位质量原油的熵产率越低,但随输量的增加,熵产率降低的幅度逐渐减少;只有适当的起始加热温度才能保证单位质量原油输送单位距离所产生的熵产率最小;对应最小熵产率的原油起始温度随管径的增大而降低。最小熵产率优化设计方法克服了热经济设计方法需要材料价格、施工费用等参数难于准确选取和所得结果与当前物价及贷款利率有关的缺点。     

Phylogenetic diversity of <Emphasis Type="Italic">Calonectria ilicicola</Emphasis> causing Cylindrocladium black rot of peanut and red crown rot of soybean in southern China

Calonectria ilicicola Boedijin & Reitsma (anamorph: Cylindrocladium parasiticum Crous, Wingfield & Alfennas) is an important pathogen worldwide, which causes Cylindrocladium black rot (CBR) in peanut (Arachis hypogaea L.) and red crown rot (RCR) in soybean [Glycine max (L.) Merr.]. We isolated the CBR and RCR pathogens from heavily diseased peanut and soybean fields in southern China and assessed their pathogenicity. Two inoculation methods were applied separately to evaluate the pathogenicity of different C. ilicicola strains on peanut cultivar Yueyou 13. Our results indicate that the Chinese C. ilicicola strains exhibited a range of virulence on peanut, with strains of soybean origin exhibiting a weak virulence relative to strains isolated from peanut. Multilocus sequence type analysis indicates that the C. ilicicola strains partitioned into two distinct clades, which were heavily structured based on geographical origin. Phylogenetic results demonstrated that the origins of C. ilicicola in southern China were multiple. This study also revealed that the backgrounds of CBR pathogens may be different from those of RCR pathogens.     

Functional Mapping of Multiple Dynamic Traits

Many biological phenomena undergo developmental changes in time and space. Functional mapping, which is aimed at mapping genes that affect developmental patterns, is instrumental for studying the genetic architecture of biological changes. Often biological processes are mediated by a network of developmental and physiological components and, therefore, are better described by multiple phenotypes. In this article, we develop a multivariate model for functional mapping that can detect and characterize quantitative trait loci (QTLs) that simultaneously control multiple dynamic traits. Because the true genotypes of QTLs are unknown, the measurements for the multiple dynamic traits are modeled using a mixture distribution. The functional means of the multiple dynamic traits are estimated using the nonparametric regression method, which avoids any parametric assumption on the functional means. We propose the profile likelihood method to estimate the mixture model. A likelihood ratio test is exploited to test for the existence of pleiotropic effects on distinct but developmentally correlated traits. A simulation study is implemented to illustrate the finite sample performance of our proposed method. We also demonstrate our method by identifying QTLs that simultaneously control three dynamic traits of soybeans. The three dynamic traits are the time-course biomass of the leaf, the stem, and the root of the whole soybean. The genetic linkage map is constructed with 950 microsatellite markers. The new model can aid in our comprehension of the genetic control mechanisms of complex dynamic traits over time.     

区域逼近与动态图形法求解大行程液压支撑机构参数及优化

为实现一种作业与运输兼用型地轮机构的状态转换,针对其结构特点研究一种非端部支撑的新型液压支撑方案,以满足在有限的安装空间内实现大工作行程的要求。在建立该机构力学及运动学模型的基础上,通过几何关系及动力约束条件进行参数的区域逼近;确定液压缸安装位置和参数的可行域后,运用动态图形模拟摆梁步进旋转时机构的运动情况,观测参数取值域曲线的运动状态,得出与可行边界线的交点,从而确定在液压系统压力16 MPa条件下,安装臂长度175 mm,安装臂距旋转点357 mm,液压缸缸体长度为916 mm,缸体内径为71 mm。研究及样机试用表明,非端部支撑对置双缸体液压支撑机构能够满足地轮状态转换的需要,且具有结构紧凑、工作行程大的特点。同时,该研究探索并证实了区域逼近与动态图形求解法在解决此类机构的优化与参数求解方面的可行性与有效性。     

试析哈萨克斯坦粮食增产的潜在因素

文章通过对哈萨克斯坦粮食生产现状的研究,分析了影响哈萨克斯坦粮食增产的潜在因素,认识到哈萨克斯坦将在世界粮食市场上发挥越来越重要的作用。     

A study on indicators and evaluation stages of aluminum tolerance in soybean

To determine an appropriate indicator and a suitable stage for evaluating tolerance of soybeans to aluminum (Al) toxin is one of the keys to effective breeding for the trait. Seventeen accessions selected as tolerant from a previous test program by using average membership index (F _Ai ) as indicator, plus one tolerant (PI.416937) and one sensitive (NN1138-2) check, were assayed in sand culture pot experiments, totaling four experiments, each for evaluation at V3, V5, V7 and V9 stage, respectively, each in a randomized complete block design with three replications, and each genotype exposed to two Al levels (0 and 480 μM). The relative values of shoot dry weight (RSDW), root dry weight (RRDW), total plant dry weight (RTDW), total root length (RTRL) and total root surface area (RRSA) as the tolerance indicators as well as F _Ai were compared. All the indicators showed significant variation in Al tolerance among genotypes over and across the leaf stages, but Genotype × Stage interactions were significant only for RTRL and RRSA, indicating that they were less stable among stages than RTDW, RSDW and RRDW. Among the latter three, RTDW was chosen as the major indicator of Al tolerance due to its relatively better stability, higher correlation with other indicators and easier measuring procedure than the others. The seedling age applicable for screening was not definitive, but V5 appeared to compromise between time spent resulting from screening the relatively older seedlings at later stages and low variation among genotypes at a younger stage. The differences of Al tolerance among the tested accessions were further detected by using RTDW, and superior Al tolerant accessions identified were PI.509080 (South Korea), N23533 and N24282 (Northeast China) and PI.159322 (USA), comparable to the putative tolerant check PI.416937 (Japan) at all vegetative stages.     

我国企业信息能力评价指标体系与测度研究

企业信息能力成为企业获取竞争优势、提高竞争力的重要因素,因此分析和评价企业信息能力具有十分重要的理论价值和实践指导意义。分析了影响企业信息能力的关键要素,构建了我国企业信息能力评价的指标体系,并提出了企业信息能力评价的测度方法,以期为我国企业信息能力的培育和提升提供指导。     

Functional mapping of genotype-environment interactions for soybean growth by a semiparametric approach

Background  

Functional mapping is a powerful approach for mapping quantitative trait loci (QTLs) that control biological processes. Functional mapping incorporates mathematical aspects of growth and development into a general QTL mapping framework and has been recently integrated with composite interval mapping to build up a so-called composite functional mapping model, aimed to separate multiple linked QTLs on the same chromosomal region.