Determinants of Capital Structure in the Presence of Supply Chain Activities of Listed Construction Firms in Vietnam

The study aims to identify the capital structure determinants in the presence of the supply chain of the listed construction firms in Vietnam. The determinants of capital structure are factors affecting firm financial leverage, including firm profitability, size, growth rate, fixed assets, liquidity, interest coverage and state ownership along with the supply chain activities. The study is based on a data of 53 listed construction firms in the Hanoi and Ho Chi Minh Stock Exchange over the period 2014-2018. The results indicated that the supply chain activities along with other determinants except profits and liquidity have a positive association with the capital structure of the listed construction firm in Vietnam. These findings guided to the policymakers that they should enhance the intensions towards the determinant of the capital structure along with supply chain activities to improve the organizational performance.

Innovation in Middle–income Economies

早稲田大学博士(学術)早大学位記番号:新9364doctoral thesi

Artificial Thawing of Frozen Ground: A Review

Understanding the freezing and thawing processes in porous media such as soils is important, especially in regions experiencing seasonal frost or permafrost. These processes have a wide range of implications as diverse as how to maintain the structural integrity of roads, railways, pipelines, and buildings, to when to plant seeds during the growth season. Thawing of frozen ground is the opposite process of ground freezing but has not received nearly as much attention as the latter in research studies or field experiments. Accurately predicting thaw depth or thaw rate is a challenging task. Many mathematical models have been proposed to describe the thawing process, with different perspectives and complexity. This paper provides an overview of historical modeling efforts made for predicting heat and mass transfer during thawing. Assumptions and premises for each model are discussed, as well as limitations and some applications. In addition, this paper reviews historical and modern approaches to thawing of frozen ground in cold regions, lists pros and cons of each method, and gives examples of applications. The review shows the need for further research and more accurate models, specifically for predicting thaw depth and thaw rates in frozen ground subjected to artificial thawing

Rare Earth-Doped BiFeO 3

Rare Earth- (RE-) doped BiFeO3 (BFO) thin films were grown on LaAlO3 substrates by using pulsed laser deposition technique. All of BFO films doped with 10% of RE show a single phase of rhombohedral structure. The saturated magnetization in the Ho- and Sm-doped films is much larger than those reported in literature and was observed at a quite low field as of 0.2 T. As for Pr- and Nd-doped BFO films, Fe2+ amount is not dominant; thus, ferromagnetism is not favored. As the RE concentration goes up to 20%, all compounds have drastically gone through a structural transition. The RE-doped BFO films have changed from rhombohedral to either pure orthorhombic phase (for Ho, Sm), or a mixed phase of orthorhombic and tetragonal (for Pr, Nd), or pure tetragonal (for Eu). We observed magnetic properties of RE-doped BFO films have significantly changed. While 20% Ho/Sm-doped BFO films have ferromagnetism degraded in comparison with the 10% doping case, the 20% Pr/Nd-doped BFO thin films, whose structure is a mixed phase, have magnetic ordering improved due to the fact that the Fe2+ amount has become greater. It seems that one can control the magnetic properties of BFO films by using appropriate RE dopants and concentrations

Arsenate reductase gene from Pityrogramma calomelanos L. enhances tolerance to arsenic in tobacco

Arsenic (As) contamination in soil, water and air is an alarming issue worldwide and has serious effects on human health and environment. Arsenic is a naturally occurring element found in rocks, soil, and water, and exposure to high levels of arsenic can lead to a range of health problems. The effects of arsenic contamination can also be felt in the environment, as it can harm plants and animals and disrupt ecological systems. The major purpose of this study was to produce transgenic plants with improved tolerance to and accumulation of arsenic via transformation of arsenate reductase gene (ArsC) into tobacco genome. Transgenic plants were screen by PCR and southern blot. Further, their tolerance and accumulation to arsenic were evaluated. In the result, we have cloned, characterized, and transformed the ArsC gene from Pityrogramma calomelanos L. (PcArsC). Its phylogenetic analysis revealed 99% homology to ArsC gene in GenBank (accession number X80057.1). Moreover, Southern blot analysis showed that ArsC gene was integrated into the tobacco genome as a single-copy. These single-copy transgenic lines showed much higher tolerance to and accumulation of As than wild type, with no other phenotypes observed. These results demonstrated that Pityrogramma calomelanos ArsC gene can improve arsenic tolerance and accumulation in transgenic tobacco lines. Thus, using Pityrogramma calomelanos L. ArsC gene for genetic engineering has potential implications in the decontamination of arsenic-containing soil

TRACKING CONTROL FOR ELECTRO-OPTICAL SYSTEM IN VIBRATION ENVIROMENT BASED ON SELF-TUNING FUZZY SLIDING MODE CONTROL

The paper presents a new method for tracking control of EOTS (Electro-Optical Tracking System) operating in mobile environment such as ship, air plane, tank and so on. This makes the base body of the EOTS has angular motion. The control alogorithm used in this paper is adaptive fuzzy sliding mode. The overall control is built and simulated in Matlab and compared with a sliding mode controller and a conventional PID controller. The simulation result illustrated the effectiveness of the proposed controlle

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam

During the cholera survey in Namdinh province (northern Vietnam) in July, 2010, one strain of Vibrio cholerae O139 was isolated from 7 environmental water samples positive for ctxA, toxR, VCO139 genes and named as V. cholerae O139, ND1 strain. This strain was lysogenic harbouring a genome similar to the filamentous phage fs1. The replicative form DNA of this phage (named as ND1-fs1, 6856 bp) was sequenced and compared with the other filamentous phages. The filamentous phage ND1-fs1 integrates into the region between ctxB and rtxA genes. The genetic organization of the CTXϕ of V. cholerae O139, strain ND1 was determined and the schematic representation of the genetic organization was shown together with the ND1-fs1 prophage

Carotenoid producing Bacillus aquimaris found in chicken gastrointestinal tracts

Pigmented spore-forming bacterial strains were isolated from the gastrointestinal tracts of chickens for screening for heat-stable carotenoid-producing strains that could be applied as feed supplements. Of the seven heat-stable pigmented isolates screened, only two, yellow Sporosarcina saromensis CH1 and red-orange Bacillus aquimaris CH9, produced pigments with typical carotenoid absorbance peaks (400–500 nm). The CH9 carotenoids exhibited higher scavenging activity (73.2%) of DPPH free radicals than the CH1 carotenoids (35.9%) and carotenoids of the reference B. indicus HU36 strain (78.4%), in comparison to 100% activity of acid ascorbic at 18.75 M as the standard. The CH9 strain produced high levels of carotenoids (439 g [g DW]-1) and formed nearly 100% spores, whereas the CH1 strain produced low levels of carotenoids (92 g [g DW]-1) and only achieved 30% sporulation. Chromatographic and spectral profiles of the carotenoids found in CH9 indicated the presence of as many as 11 different carotenoid types closely related to 1-HO-demethylspheroidene and keto/hydroxyl derivatives of carotene. We successfully produced concentrated orange CH9 spore powder at a high concentration of 6.1 × 1011 CFU g-1; these spores were much more heat-stable (66% survival at 80°C for 20 min) than the reference B. indicus HU36 spores (9% survival at 50°C for 20 min). In conclusion, B. aquimaris CH9 is a promising probiotic carotenoid-producing strain, with heat-stable spores that should withstand the heat-treatment processing required for feed and food supplement production

Characteristics of Antibiotic-resistant E. coli Isolated from Perfume River in Hue City, Vietnam

Antibiotic resistant bacteria (ARB) in aquatic environments is attracting increasing attention. However, the spread of ARB along Perfume River in Hue City is poorly understood. This study aimed to phenotypically and genotypically characterize β-lactam- and fluoroquinolone-resistant Escherichia coli isolates from this river. Water samples were collected from the urban, rural, agricultural, and less-affected areas in March 2020. E. coli susceptibility to seven commonly employed antibiotics was analyzed using the disk diffusion method, and the antibiotic resistance genes (ARGs), qnrA, qnrB, qnrS, TEM, SHV, and CTX-M, were identified using polymerase chain reaction (PCR) and DNA sequencing. The antibiotic susceptibility patterns of E. coli revealed that the rate of amoxicillin resistance was the highest (60%). PCR assays and sequencing of 12 β-lactam-resistant E. coli isolates indicated the presence of blaTEM and blaCTX-M-15 in 58.3% and 16.7% of the isolates, respectively. Only one of four fluoroquinolon -resistant E. coli isolates harbored the qnrS, while qnrA or qnrB genes were not detected. These findings suggest that this water may be an essential source of transmissible ARGs in Hue City, which may have a detrimental impact on the people living in this area