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Endocrine disruptors that may be present in plastic wastes can leach into surface water, pollute the environment and our drinking water; they must be monitored. In this study, an electrochemical sensor based on a metal organic framework (Cu, Zr-BTC) combined with carbon nanotubes (CNT) was developed for rapid on-site detection of bisphenol A—the most widely used monomer in plastics production. The Cu, Zr-BTC/CNT composite was first prepared by a solvothermal process in DMF solvent at 100 °C. For the first time, the Zr-based MOF with high proton conductivity was combined with Cu-based MOF with large active area in the same framework to provide an efficient platform for electrochemical detection. Morphological and structural studies revealed the coordination of Cu2+ and Zr4+ ions with organic ligands in a highly porous framework (active surface area up to 673 m2 g−1). The use of highly conductive carbon nanotube material is to improve the recorded electrochemical signals. The developed bisphenol A sensor showed a linear response for bisphenol A concentrations from 2 to 50 µM, with a detection limit down to 0.5 µM and a sensitivity of 0.45 µA.µM−1 cm−2. The sensors produced gave reproducible results (relative standard deviation of less than 7%) and were stable (relative standard deviation less than 12% after several days of storage). Tests on real samples were performed on Hanoi tap water and showed a satisfactory recovery (92–95%). The results were validated using high performance liquid chromatography. These results demonstrate the possibility of using such MOF materials in sensor applications. [ABSTRACT FROM AUTHOR]

Manuscript type: Research paper Research aims: Ownership structure is crucial to corporate governance as it explains sources of the agency conflicts. Despite the studies performed on the roles and impacts of diverse corporate ownership on corporate performance and corporate governance, the role of state-owned holding company (SOH), as a particular type of state ownership, has not been duly explored. This study addresses the gap by examining the relationship between SOH ownership in listed companies, and how they perform. Design/Methodology/Approach: This quantitative study applies empirical models which test the impact of the different ownerships of firms on firm performance by controlling board characteristics. Regression models are used to test the explanatory power of the variables of interest. Data are collected from all the non-financial firms listed on the Ho Chi Minh Stock Exchange (HOSE), and the Hanoi Stock Exchange (HNX), prior to 31 December, 2009. The selected period equals to a balanced panel dataset of 242 firms for a period of 9 years, ranging from 2009 to 2017. Research findings: The results show that firms with SOH ownership, or SOH-linked companies (SLCs), tend to deliver superior returns. They also enjoy higher valuations than government-linked companies (GLCs), and non-GLCs. There is evidence to show that when the SOH holds a dominant ownership, it exercises positive control over firms, thereby resulting in better market performance. Theoretical contribution/Originality: The evidence of this study focusses on Vietnam. It is also consistent with the findings of other countries. This study confirms that the SOH model mitigates the agency problems that exist in companies with state capital. This study also provides empirical evidence which support that SOH is a mechanism that resolves the various problems noted in state-linked companies caused by conflicting objectives, political influences, and poor management and governance. Practitioner/Policy implications: This study offers regulators a reference which can be used when making policies that would suit the environment of Vietnam. In that regard, it offers an indepth look into the SOH model which is further encouraged for replication. The outcome derived from this study can help managers to make adjustments and improvements in company's corporate governance so as to achieve better firm performance. This study also helps investors and other stakeholders to better understand the problems arising from corporate governance in Vietnam. In that regard, the outcome can be used to help them make better decisions such as investments, choosing board directors, or making corporate governance policies. Research limitation/Implications:: This study faces some limitations, among which is that it focusses solely on firm performance. [ABSTRACT FROM AUTHOR]

Rapid and unplanned urbanization leads to temperature rise, urban vegetation decrease and built-up land increase, forming an urban heat island (UHI). This study investigated the effects of changes in vegetation and built-up land on land surface temperature (LST) in summer, based on remotely sensed images. LST was first retrieved by means of the Radiative Transfer Model (RTM). Scatterplots and an univariate linear regression model (ULRM) were first employed to independently measure the influence of NDVI on LST, and of NDBI on LST, respectively. In order to assess the effects of changes in vegetation and built-up land on LST, a multivariate linear regression model (MLRM) was finally employed to improve the accuracy of the predicted model in the identification of the joint effect of both the normalized difference vegetation index (NDVI) and the normalized difference built-up index (NDBI) on LST. The result from the case from the Hanoi Metropolitan Area (HMA), Vietnam using Landsat-5 TM and Landsat-8 OLI/TIRS time-series images during the 1996-2016 period shows that there exists a negative effect of built-up land and a positive effect of vegetation on LST. In addition, indications of intensifying UHI effects were detected in the HMA, especially tending to expand faster and wider to the parts of western, north-western and south-western HMA during the 1996-2007 period. These findings suggest that vegetation weakens the effect of UHIs, whereas, built-up land greatly strengthens the effect of UHIs in the HMA. [ABSTRACT FROM AUTHOR]

Our study recorded the presence of Mesocriconema sphaerocephalum on carrot in Hanoi city and Hai Duong province in Vietnam. This species was identified by morphometric, morphological characterizations, and molecular characterization of D2D3 of 28S rDNA sequence. To our knowledge, this is the first report of M. sphaerocephalum on carrot in Vietnam. [ABSTRACT FROM AUTHOR]