Updating Insights into the Catalytic Domain Properties of Plant Cellulose synthase (CesA) and Cellulose synthase-like (Csl) Proteins

The wall is the last frontier of a plant cell involved in modulating growth, development and defense against biotic stresses. Cellulose and additional polysaccharides of plant cell walls are the most abundant biopolymers on earth, having increased in economic value and thereby attracted significant interest in biotechnology. Cellulose biosynthesis constitutes a highly complicated process relying on the formation of cellulose synthase complexes. Cellulose synthase (CesA) and Cellulose synthase-like (Csl) genes encode enzymes that synthesize cellulose and most hemicellulosic polysaccharides. Arabidopsis and rice are invaluable genetic models and reliable representatives of land plants to comprehend cell wall synthesis. During the past two decades, enormous research progress has been made to understand the mechanisms of cellulose synthesis and construction of the plant cell wall. A plethora of cesa and csl mutants have been characterized, providing functional insights into individual protein isoforms. Recent structural studies have uncovered the mode of CesA assembly and the dynamics of cellulose production. Genetics and structural biology have generated new knowledge and have accelerated the pace of discovery in this field, ultimately opening perspectives towards cellulose synthesis manipulation. This review provides an overview of the major breakthroughs gathering previous and recent genetic and structural advancements, focusing on the function of CesA and Csl catalytic domain in plants.     

Interference suppression for the LTE uplink

Interference cancellation is expected to have significant importance for next-generation wireless communication systems due to various co-channel deployment scenarios and denser frequency reuse. In this study, an interference cancellation receiver that exploits the unique characteristics of single-carrier frequency-division multiple access based systems is proposed. The proposed receiver suppresses the co-channel dominant interference by blanking frequency-domain samples where the desired and interfering signals overlap. In order to improve the performance, demodulation and regeneration stages can be introduced and repeated multiple times. Further enhancement is possible by initially accommodating a group of reliable symbols before the iterations. The simulation results indicate that proposed methods work particularly well for low overlap ratios compared to interference coordination and no cancellation schemes.     

Bundling decisions in supply chains

Firms often sell products in bundles to extract consumer surplus. While most bundling decisions studied in the literature are geared to integrated firms, we examine a decentralized supply chain where the suppliers retain decision rights. Using a generic distribution of customers’ reservation price we establish equilibrium solutions for three different bundling scenarios in a supply chain, and generate interesting insights for distributions with specific forms. We find that (i) in supply chain bundling the retailer’s margin equals the margin of each independent supplier, and it equals the combined margin when the suppliers are in a coalition, (ii) when the suppliers form a coalition to bundle their products the bundling gain in the supply chain is higher and retail price is lower than when the retailer bundles the products, (iii) the supply chain has more to gain from bundling relative to an integrated firm, (iv) the first-best supply chain bundling remains viable over a larger set of parameter values than those in the case of the integrated firm, (v) supplier led bundling is preferable to separate sales over a wider range of parameter values than if the retailer led the bundling, and (vi) if the reservation prices are uniformly distributed bundling can be profitable when the variable costs are low and valuations of the products are not significantly different from one another. For normally distributed reservation prices, we show that the bundling set is larger and the bundling gain is higher than that for a uniform distribution.     

Dynkin Diagram Sequences and Stabilization Phenomena

We continue the study of stabilization phenomena for Dynkin diagram sequences initiated in the earlier work of Kleber and the present author. We consider a more general class of sequences than that of this earlier work, and isolate a condition on the weights that gives stabilization of tensor product and branching multiplicities. We show that all the results of the previous article can be naturally generalized to this setting. We also prove some properties of the partially ordered set of dominant weights of indefinite Kac–Moody algebras, and use this to give a more concrete definition of a stable representation ring. Finally, we consider the classical sequences B _n , C _n , D _n that fall outside the purview of the earlier work, and work out some easy-to-describe conditions on the weights which imply stabilization.     

The DJL Conjecture for CP Matrices over Special Inclines

Drew, Johnson, and Loewy conjectured that for n ≥ 4, the CP-rank of every n × n completely positive real matrix is at most [n²/4]. While this conjecture has recently been disproved for completely positive real matrices, we show that this conjecture is true for n × n completely positive matrices over certain special types of inclines. In addition, we prove an incline version of Markham's theorems which gives sufficient conditions for completely positive matrices over special inclines to have triangular factorizations.     

病态线性方程组新的Jacobi迭代解法

给出了解病态线性方程组的一种新的Jacobi迭代算法,并证明了算法的收敛性;通过具体算例说明了算法的实用性和有效性.     

广义严格对角占优矩阵新的判定准则

In this paper we provide the new criteria for a strictly generalized diagonally dominant matrix, and it proves by an example that the results of this paper extend the results in[6]. In addition, we obtain the criteria of the nonsingular M-matrix.     

空间网格结构动力分析的非线性模态方法

空间网格结构因自由度数多且无简化的力学模型,非线性动力分析通常要耗费大量时间．传统的非线性模态方法用于求解多高层结构的局部非线性问题已获得良好的效果,但对系统非线性问题的应用尚缺少研究．对比分析多高层结构和空间网格结构动力性能差异,指出网格结构动力非线性分析存在的问题．以主振型理论和切线刚度分离法为基础,将非线性模态方法用于几何非线性效应显著的空间网格结构动力分析．通过对运动方程的非线性恢复力进行拆分,形成线性表达形式,然后解耦到主振型所在的广义坐标系,以达到缩减自由度数量的目的．并通过实例验证非线性模态方法的高效性与适用性．     

浙江梅山岛附近海域大型底栖动物和游泳动物的群落组成及其与环境因子的关系

2020年9月对梅山岛附近海域的大型底栖动物和游泳动物进行了定量调查,分析了梅山岛附近海域大型底栖动物和游泳动物的群落组成和数量特征,包括群落种类组成、丰度、生物量和优势种,并对大型底栖动物和游泳动物的群落组成、数量特征与水深、悬浮物、营养盐等重要环境因子进行了相关性分析.结果表明:梅山岛附近海域共有大型底栖动物5门16种,其中环节动物门5种、软体动物和节肢动物门各4种、棘皮动物门2种、脊索动物门1种;梅山岛附近海域大型底栖动物平均丰度为12.73 ind·m^-2,平均生物量为2.87 g·m^-2,其中纵肋织纹螺(Nassarius variciferus)为研究海域唯一的优势种.游泳动物共有55种,其中鱼类29种、甲壳动物23种、软体动物门中头足纲动物2种、腔肠动物1种;游泳动物在整个研究海域的尾数密度为24.77×10³ind·km^-2,重量密度为144.53 kg·km^-2;游泳动物优势种共9种,其中龙头鱼(Harpadon nehereus)的优势度最高,口虾蛄(Ora...     

关于“一类非奇异H-矩阵判定的新条件”一文的注记

通过构造新的正对角因子元素，本文给出了几个判定非奇异H-矩阵新的充分条件，改进和推广了"一类非奇异H-矩阵判定的新条件"一文的主要结果，并用数值例子说明了文中结果判定范围的更加广泛性.