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Electronic platforms have been increasingly popular for executing large corporate bond orders by asset managers, who in turn have to assess the quality of their executions via Transaction Cost Analysis (TCA). One of the challenges in TCA is to build a realistic benchmark for the expected transaction cost and to characterize the price impact of each individual trade with given bond characteristics and market conditions. Taking the viewpoint of retail investors, this paper presents an analytical methodology for TCA of corporate bond trading. Our analysis is based on the TRACE Enhanced dataset; and starts with estimating the initiator of a bond transaction, followed by estimating the bid-ask spread and the mid-price dynamics. With these estimations, the first part of our study is to identify key features for corporate bonds and to compute the expected average trading cost. This part is on the time scale of weekly transactions, and is by applying and comparing several regularized regression models. The second part of our study is using the estimated mid-price dynamics to investigate the amplitude of its price impact and the decay pattern of individual bond transaction. This part is on the time scale of each transaction of liquid corporate bonds, and is by applying a transient impact model to estimate the price impact kernel using a non-parametric method. Our benchmark model allows for identifying abnormal transactions and for enhancing counter-party selections. A key discovery of our study is the price impact asymmetry between customer-buy orders and consumer-sell orders. [ABSTRACT FROM AUTHOR]

BACKGROUND: Drought stress (DS) is the main abiotic stress that maize suffers during its whole growth period, and maize is also sensitive to DS. It had been demonstrated that DS could improve the quality of normal maize starch. However, waxy maize, which has special properties, has not been explored in depth, which limits the breeding and cultivation of waxy maize varieties and the application of waxy maize starch. Therefore, in this study, we investigated the effects of DS on the biosynthesis, structure, and functionality of waxy maize starch. RESULTS: The results showed that DS decreased the expression level of SSIIb, SSIIIa, GBSSIIa, SBEI, SBEIIb, ISAII, and PUL, but increased the expression level of SSI and SBEIIa. DS did not change the average chain length of amylopectin, while increased the relative content of fa chains (RCfa) and decreased the RCfb1 and RCfb3. Furthermore, DS decreased the amylose content, amorphous lamellar distance da, semi‐crystalline repeat distance, and average particle size, whereas it increased the relative crystallinity, crystalline distance dc, the content of rapidly digested starch in the uncooked system and resistant starch content in both the uncooked and cooked system. Conclusions: For waxy maize, DS could raise the relative expression level of SSI and SBEIIa, thus increasing RCfa. The larger number of RCfa could create steric hindrance, which can lead to producing more resistant starch in waxy maize starch. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Bivariate flow cytometry (FC) sorting with forward scatter (FSC) and side scatter (SSC) is a recently established novel technique to separate starch granules. However, the forming mechanism of starch FC-dependent population patterns (i.e. the number of subgroups (NS) and FSC/SSC-dependent distribution patterns) remain partly elusive. For this, the correlation of granular size and multi-scale structure of native starches and FC-dependent population patterns was investigated through employing a wide range of native starches originating from different species involving cereal-, pulse-, and tuber crops. Results showed NS was pertinent with particle size, amylose content (AC), amylopectin chains length distribution, lamellar structure, short-range ordered structure. The distinct NS was determined by impacts of native starch FSC / SSC-dependent distribution patterns. Specifically, starch granular size significantly correlated with both FSC and SSC-dependent distribution patterns. The proportion of chains with DP 6–12 was the intra-molecular decisive factor to influence short-range ordered structure, finally leading to FSC-dependent distribution patterns. By contrast, AC was another intra-molecular index to determine SSC-dependent distribution patterns through affecting lamellar structure and short-range ordered structure. • Side scatter (SSC) is vulnerable to short-range ordered and lamella structures. • Forward scatter (FSC) is sensitive to short-range ordered structure. • Starch particle size affect distribution patterns of both FSC and SSC. • The correlation of starch features and FSC/SSC exists in limited range. [ABSTRACT FROM AUTHOR]

We investigated the effects of drought stress (DS) on maize varieties with different amylose content (AC). In starches with AC of 33 %, DS increased the contents of amylopectin (AP) chains with a degree of polymerization (DP) > 36 and decreased the AP chains with DP ≤ 36, while the AC was unchanged. DS decreased the crystallinity, the thickness of both amorphous and crystalline lamellae, and average granular size. In contrast, the digestibility increased. For starches with AC of 45 %, DS increased the content of AP chains with DP > 24 and AC, while the contents of AP chains with DP ≤ 24 decreased. DS produced starch with thinner crystalline lamellae, thicker amorphous lamellae, more elongated and larger granules. The digestibility of the starches decreased. In starches with AC of 53 %, moderate DS led to similar structural and functional changes as found for starches with AC of 45 %. Finally, severe DS resulted in the decrease of AC. [Display omitted] [ABSTRACT FROM AUTHOR]