基于双正则化的图像超分辨率盲重建

图像超分辨率重建是利用数字信号处理技术由一系列低分辨率观测图像得到高分辨率图像。大多数重建算法假设成像系统的模糊特性也即点扩散函数(PSF)已知,然而实际的应用环境下PSF事先不知道或部分知道。为此,将未知PSF模型化,提出基于双正则化的图像超分辨率盲重建算法,并且正则化作用的强度随重建图像局部光滑程度的变化而自适应地改变,以便能保护图像细节同时抑制平滑区域的噪声。求解过程中采用交替最小化方法估计PSF参数和高分辨率图像,并随着迭代次数的增加逐步提高每次寻优的精度以节省计算开销。实验结果表明,该算法能够比较准确地估计出PSF参数并取得较好的图像重建效果。     

Genetic Variations of Brassica Cultivars for P Acquisition in a P Stress Environment and Comparison of P Sources for Sustainable Crop Management

To compare the growth performance of Brassica in a phosphorus (P) stress environment and response to added P, six Brassica cultivars were grown in pots for 49 days after sowing, using a soil low in P [sodium bicarbonate (NaHCO₃)–extractable P = 3.97 mg kg^?1, Mehlich III–extractable P = 6.13 mg kg^?1] with (+P = 60 mg P kg^?1 soil) or without P addition (0P). Phosphorus‐stress markedly reduced biomass accumulation and P uptake by roots and shoots. However, root–shoot ratio remained unaffected, implying that relative partitioning of biomass into roots and shoots had little role to play in shoot dry matter (SDM) production by cultivars. Biomass correlated significantly (P < 0.01) with total P uptake. Under P stress, the cultivars that produced greater root biomass were able to accumulate more total P content (r = 0.95^**), which in turn was related positively to SDM and total biomass (r > 0.89^**) and negatively to P‐stress factor (r = ?0.91^**). There was no correlation between P efficiency (PE) (relative shoot growth) and plant P, but PE showed a very significant correlation with shoot P content and SDM. Wide differences in growth and better performance of cultivars such as ‘Brown Raya’ and ‘Con‐1’ under P stress encouraged screening of more germplasm, especially in the field, to identify P‐tolerant cultivars.

In another study, potential relative agronomic effectiveness (RAE) of sparingly soluble P sources was investigated by growing two contrasting cultivars. The P sources incorporated into soil at 0, 10, 25, 50, and 100 mg P Kg^?1 were (i) powdered Jordan rock P (RP), (ii) triple superphosphate (TSP), (iii) powdered low‐grade TSP [TSP(PLG)], (iv) a mixture of RP + TSP compacted into pellets at 50:50 P ratio [RP + TSP(PelC)], and (v) a mixture of powdered RP + TSP at 50:50 P ratio [RP + TSP(PM)]. The RP was low in RAE and only 5 and 29% as effective as TSP in producing dry matter (DM) of P‐sensitive ‘B.S.A.’ and P‐tolerant ‘Brown Raya’ cultivars, respectively. There were no significant differences between TSP and RP + TSP(PelC) in DM yield of ‘Brown Raya,’ whereas, in the case of ‘B.S.A.’ RP + TSP(PM) was significantly less effective than RP + TSP(PelC) compared with TSP. Combined utilization of superior genome and P sources [such as TSP(PLG) and RP + TSP(PelC)] produced from low‐grade RP (that cannot be used either for direct application or acidulated P fertilizers) can be used as an alternative strategy for sustainable crop production, especially in resource‐poor environments. Further field trials at the level of cropping systems are needed.     

草鱼成纤维细胞gcngr1基因的表达分析

Ngr1(nogo-66 receptor)是在哺乳类上发现的一种神经元受体,可调节轴突的可塑性并抑制损伤中枢神经系统(CNS)的再生,最新研究还发现它是哺乳动物呼肠孤病毒(mammalian reovirus)的神经受体。草鱼呼肠孤病毒(grass carp reovirus,GCRV)可引发草鱼(Ctenopharyngodon idellus)出血病导致高死亡率,开展GCRV受体相关研究可有助于了解病毒的致病机制。该研究在草鱼吻端成纤维细胞(PSF)中克隆到草鱼ngr1 c DNA序列(下文简称为gcngr1),发现其与哺乳动物呼肠孤病毒神经受体基因Ngr1有相似的结构序列;采用q RT-PCR方法检测该基因在PSF细胞的表达情况,结果显示受草鱼呼肠孤病毒(GCRV-GD108株)感染后gcngr1 m RNA的表达量显著上升,与病毒的增殖趋势基本一致;病毒经病毒抗体孵育后再感染PSF细胞,细胞中病毒的增殖水平下降,gcngr1m RNA的表达量也显著下降。该研究结果提示gcngr1与病毒的感染相关,为进一步分析gcngr1是否为GCRV神经元受体提供依据。     

Phosphorus Stress Induced Variations in Growth Behavior and P Efficiency among Brassica Cultivars Grown with Sparingly Soluble P Sources

To evaluate phosphorus (P)–stress–induced relative growth responses, P-efficiency characteristics, P remobilization, and redesign in root architectural systems, Brassica cultivars were grown with sparingly soluble rock phosphate and calcium phosphate [Ca₃(PO₄)₂] or with low/high P supply in solution and sand culture experiments. Tested cultivars showed considerable genetic diversity in biomass accumulation, concentration and contents of P, P-stress factor (PSF), and P-efficiency characteristics [P-utilization efficiency (PUE), P efficiency (PE), and P-efficiency ratio (PER)]. Statistically significant correlations were observed between P efficiency and growth parameters. Elongation rates of primary roots decreased but the length of lateral roots and branched zone elongation rates increased under P starvation. Cultivars remobilized P from metabolically inactive to active sites in P-stressed plants that may have helped low-P-tolerant cultivars to establish a better rooting system, which provided basis for enhanced P-use efficiency and tolerance against P stress. Cultivars depicting high P efficiency and low PSF values were more tolerant and are a better choice to grow under P-stress environments.     

运动模糊图像经典复原算法

根据运动模糊图像的特点,介绍了运动模糊图像退化模型.在该模型的基础上分析了模糊参数在已知和未知两种情况下模糊图像的PSF(point spread function点扩散函数)的确定方法,并对其进行实例验证说明.基于该退化模型和模糊参数确定方法详细地对现有的各非盲复原和盲复原算法进行了介绍与分析.为了更直观地观察各复原算法的复原效果,对各算法进行了仿真实验并比较了它们的优缺点和总结了其应用范围,指出了今后图像处理领域的发展方向,对现实的图像技术运用具有指导意义.     

草鱼jam-a分子在胚胎幼鱼期及受GCRV感染PSF细胞的表达分析

草鱼呼肠孤病毒(Grass carp reovirus, GCRV)可引发草鱼(Ctenopharyngodon idellus)出血病,导致高死亡率。草鱼吻端成纤维细胞(Grass carp snout fibroblast cells, PSF)是GCRV的敏感细胞系。JAM-A (Junctional adhesion molecule A)为免疫球蛋白超家族成员,是多种病毒的细胞受体。本研究在前期克隆到草鱼3种jam-a基因,命名为gcjam-a1,gcjam-a2和gcjam-a3。在获取ORF序列的基础上,利用qRT-PCR分析了3种gcjam-a在草鱼胚胎及幼鱼不同发育时期及PSF细胞中受GCRV(GD108株)感染前后的表达模式。结果显示,检测的13个胚胎及幼鱼发育时期中,gcjam-a1在未受精卵中高表达,在受精卵至出膜前的胚胎表达水平均较低;从出膜后1~3 d表达量开始上升;出膜6~15 d均呈高水平表达。gcjam-a2与gcjam-a3在草鱼胚胎及幼鱼发育各阶段表达水平较低。在无病毒感染的PSF细胞中,gcjam-a只有少量表达。受GCRV-GD108感染后,病毒S7基因在PSF细胞中的拷贝数随时间呈显著上调趋势,gcjam-a的表达量也有不同程度的上调,mRNA上调水平为gcjam-a1>gcjam-a2>gcjam-a3。本研究证实了3种gcjam-a基因在PSF细胞中的表达均与GCRV-GD108感染相关,其中,gcjam-a1的表达水平受GCRV-GD108感染影响最大,同时,它在孵化出膜后表达上升,推测它可能与病毒的感染更相关。gcjam-a1可作为下一步GCRV与宿主互作研究中的候选分子。     

Relative Phosphorus Utilization Efficiency,Growth Response,and Phosphorus Uptake Kinetics of Brassica Cultivars under a Phosphorus Stress Environment

Abstract

Plants grown in highly weathered or highly alkaline calcareous soils often experience phosphorus (P) stress but never a P‐free environment. Thus, applications of mineral P fertilizers are often required to achieve maximum yield, but recovery of applied P fertilizers is notoriously low. Phosphorus deprivation elicits a complex array of morphological, physiological, and biochemical adaptations among plant species and genotypes to enhance P acquisition and utilization efficiency. Ten Brassica cultivars were grown hydroponically to investigate their relative efficiency to utilize deficiently (20‐µM) and adequately (200‐µM) supplied P, using Johnson's modified solution. Cultivars differed significantly (P<0.001) in biomass accumulation. Orthophosphate concentration and uptake in shoot and root, absolute and relative growth rate, and P‐utilization efficiency (PUE) were also significantly different among various Brassica cultivars. Root‐shoot ratio and specific absorption rate were substantially increased in plants subjected to low P supply. Shoot and root dry‐matter yield as well as total biomass production correlated significantly (P<0.01) with their total P uptake and PUE. Cultivars, which were efficient in P utilization, were also efficient accumulators of biomass under adequate as well as deficient levels of P supply. As part of the study, kinetic parameters of P uptake were evaluated for six contrasting Brassica cultivars in PUE, grown in nutrient solution. The kinetic parameters related to P influx were maximal transport rate (Vmax), the Michaelis–Menten constant (Km), and the external concentration when net uptake is zero (Cmin). Lower Km and Cmin values were indicative of P‐uptake ability of the cultivars, evidencing their adaptability to P‐stress conditions. In another experiment, six cultivars were exposed to no P nutrition for 27 days after initial feeding on optimum nutrition for 14 days. All the cultivars retranslocated P from aboveground parts to their roots during growth in P‐free conditions, the magnitude of which was variable in different cultivars. Phosphorus concentration at 41 days after transplanting was higher in developing leaves than developed leaves. Translocation of absorbed P from metabolically inactive sites to active sites in plants growing under P‐stress conditions may have helped the tolerant cultivars to establish a better rooting system, which provided basis for tolerance against P‐deficiency stress and increased PUE.     

基于ITFN-DEMATEL的联合收割机驾驶人员关键行为形成因子研究

为提高联合收割机驾驶过程中的人机交互安全性，研究驾驶人员的关键行为形成因子(PSF)。在PSF系统化分类方法的基础上，采用文献分析法和专家判断法构建联合收割机驾驶PSF体系；结合梯形直觉模糊数(ITFN)与决策试验与评价实验室(DEMATEL)方法，确定PSF的专家直觉评分集并进行模糊化处理，构建直觉关系模糊影响矩阵，通过模糊运算转化为综合关系模糊影响矩阵，计算PSF的中心度和原因度，提出关键因子；最后运用计算机仿真对结论进行灵敏度分析。结果表明：PSF关系模型有效，能正确描述PSF之间的因果关系；19个PSF相互之间的综合影响度为2.87，中心度均值为5.75，其中态度、技能、经验、显示方式、显示界面布局、操纵装置布局、前向视野、安全教育、作业监管、操作规程、监管机构等11个要素的中心度大于均值或原因度高于0。