THE RELATIONSHIP BETWEEN PUBLIC SERVICE MOTIVATION, WORK ENJOYMENT, AND TASK PERFORMANCE: A PRELIMINARY STUDY OF HEALTHCARE WORKERS IN VIETNAM

This study aimed to examine the impact of health workers' public service motivation during their participation in response to the Covid-19 pandemic at a time of the highest number of infections and deaths in Vietnam. This study was conducted through a cross-sectional survey using an intentional sampling technique (n=200). In addition, Structural Equation Modeling (SEM) was applied to illustrate the proposed hypotheses. We found that compassion in the workplace, self-sacrifice, and attraction to policy-making impacted work enjoyment positively and significantly. In particular, there was a positive and significant relationship between work enjoyment and task performance but no evidence of the relationship between Commitment to the public interest and work enjoyment. This study further demonstrates the importance of public service motivation of health workers in pandemic response, as previous studies have found. This finding suggests that the government and policymakers in Vietnam should develop policies to promote health workers' public service motivation during their engagement in response to the health crisis.&nbsp

1M parameters are enough? A lightweight CNN-based model for medical image segmentation

Convolutional neural networks (CNNs) and Transformer-based models are being widely applied in medical image segmentation thanks to their ability to extract high-level features and capture important aspects of the image. However, there is often a trade-off between the need for high accuracy and the desire for low computational cost. A model with higher parameters can theoretically achieve better performance but also result in more computational complexity and higher memory usage, and thus is not practical to implement. In this paper, we look for a lightweight U-Net-based model which can remain the same or even achieve better performance, namely U-Lite. We design U-Lite based on the principle of Depthwise Separable Convolution so that the model can both leverage the strength of CNNs and reduce a remarkable number of computing parameters. Specifically, we propose Axial Depthwise Convolutions with kernels 7x7 in both the encoder and decoder to enlarge the model receptive field. To further improve the performance, we use several Axial Dilated Depthwise Convolutions with filters 3x3 for the bottleneck as one of our branches. Overall, U-Lite contains only 878K parameters, 35 times less than the traditional U-Net, and much more times less than other modern Transformer-based models. The proposed model cuts down a large amount of computational complexity while attaining an impressive performance on medical segmentation tasks compared to other state-of-the-art architectures. The code will be available at: https://github.com/duong-db/U-Lite.Comment: 6 pages, 7 figure

Quantifying organic carbon storage and sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province using carbon stable isotope

The objective of this study is to quantify the organic carbon (OC) storage and its sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province by analyzing TOC (total organic carbon), TN (total nitrogen), C/N ratios, δ13C isotopes and sediment grain sizes. The results showed that the fine-grained sediment fraction (63 µm) ranged from 8.58 to 82.10%; TOC, TN contents, C/N ratios and δ13C values ranged from 0.21 to 10.20%, 0.01 to 0.34%, 15.07 to 46.09 and –27.75 to –25.84‰, respectively. The variation of δ13C and C/N ratios, and the correlation between TOC, TN and the fine-grained sediment fractions indicated that mangrove forests play important roles in OC sequestration and accumulation of fine-grained sediments. The OC storage in sediments varied from 16.7 to 78.3 MgC ha-1 with an average of 57.2 ±14.9 MgC ha-1. Nowadays, the mangrove forest area in Dong Rui is about 2194.1 ha, thus, the total OC in sediment pool up to 45 cm in depth, contained 1.26(±0.3)×105 MgC, equivalent to 4.6(±1.2)×105 Mg CO2. These results demonstrated that the conservation of Dong Rui mangrove forest not only provides opportunities for coastal protection and disaster mitigation and other provision values, but also enhancing carbon sequestration and offsetting greenhouse gas emissions.References Alongi, D.M., 2011. Carbon payments for mangrove conservation: ecosystem constraints and uncertainties of sequestration potential. Environmental Science Policy 14, 462-470. Alongi, D.M., Sasekumar, A., Chong, V.C., Pfitzner, J., Trott, L.A., Tirendi, F., Dixon, P., Brunskill, G.J., 2004. Sediment accumulation and organic material flux in a managed mangrove ecosystem: estimates of land - ocean - atmosphere exchange in peninsular Malaysia. Marine Geology 208, 383-402. Bouillon, S., Connolly, R., Lee, S., 2008. Organic matter exchange and cycling in mangrove ecosystems: recent insights from stable isotope studies. Journal of Sea Research 59, 44-58. Bouillon, S., Rao, A.V.V.S., Koedam, N., Dahdouh-Guebas, F., Dehairs, F., 2003. Sources of organic carbon in mangrove sediments: variability. Hydrobiologia 495, 33-39. Christensen, B., 1978. Biomass and primary production of Rhizophoraapiculata Bl. in a mangrove in southern Thailand. Aquat Bot 4, 43-52. Donato, D.C., Kauffman, J.B., Murdiyarso, D., Kurnianto, S., Stidham, M., Kanninen, M., 2011. Mangroves among the most carbon - rich forests in the tropics. Nature Geoscience 4, 293-297. Furukawa, K., Wolanski, E., 1996. Sedimentation in mangrove forests. Mangroves Salt Marshes 1, 3-10. Hedges, J.I., Keil, R.G., 1995. Sedimentary organic matter preservation: an assessement and speculative synthesis. Marine Chemistry 49, 137-139. Kauffman, J.B., Donato, D.C., 2012. Protocols for the measurement, monitoring and reporting of structure, biomass and carbon stocks in mangrove forests, 86 pp., Center for International Forest Research, Bogor, Indonesia. Kristensen, E., Bouillon, S., Dittmar, T., Marchand, C., 2008. Organic carbon dynamics in mangrove ecosystems: A review. Aquat Bot 89, 201-209. Lamb, A., Wilson, G., Leng, M., 2006. A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material. Earth Science Reviews 75, 29-57. Lovelock, C.E., Ruess, R.W., Feller, I.C., 2011. CO2 efflux from cleared mangrove peat. PLoS ONE 6, 1-4. Ong, J.E., 1993. Mangroves - a carbon source and sink. Chemosphere 27, 1097-1107. Quy, T.D., Tue, N.T., 2011. Spatial distribution of total organic carbon (TOC), total nitrogen (TN), TOC/TN ratio, and stable carbon isotopes value (δ13C) in surface sediments of Tien Yen Bay, northeast Vietnam. Vietnam Journal of Earth Sciences 33, 615-624 (In Vietnamese). Reimers, C.E., Suess, E., 1983. The partitioning of organic carbon fluxes and sedimentary organic matter decomposition rates in the ocean. Marine Chemistry 13, 141-168. Richard, M., Angus, M., Tim, H., 2011. The potential for mangrove carbon projects in Vietnam. SNV REDD+, Hanoi. Schumacher, B.A., 2002. Methods for the determination of total organic carbon in soils and sediments. U.S. Environmental Protection Agency, Washington. Siikamäki, J., Sanchirico, N., Jardine, J., McLaughlin, S., Morris, D.F., 2012. Blue carbon: global options for reducing emissions from the degradation and development of coastal ecosystems. Resources for future, Washington. Spalding, M., Kainuma, M., Collins, L., 2010. World atlas of mangroves. Earthscan from Routledge, London. Tuan, H.V., Quy, T.D., Vuong, N.V., Nhuan, M.T., 2012. Orientation of functional zoning for sustainable use of environment and natural resources in Tien Yen Bay. Vietnam Journal of Earth Sciences 34, 486-494 (In Vietnamese). Tuan, M.S., Hanh, N.T.H., 2009. Carbon accumulation of Kandeliaobovata (Sheue, Liu Yong) plantation in the coastal area of Giao Thuy district, Nam Dinh province. Journal of Biology 31, 57-65 (In Vietnamese). Tue, N.T., Dung, L.V., Nhuan, M.T., Omori, K., 2014. Carbon storage of a tropical mangrove forest in Mui Ca Mau National Park, Vietnam. Catena 121, 119-126. Tue, N.T., Hamaoka, H., Sogabe, A., Quy, T.D., Nhuan, M.T., Omori, K., 2011. The application of δ13C and C/N ratios as indicators of organic carbon sources and paleoenvironmental change of the mangrove ecosystem from Ba Lat Estuary, Red River, Vietnam. Environmental Earth Sciences 64, 1475-1486. Tue, N.T., Ngoc., N.T., Quy, T.D., Hamaok, H., Nhuan, M.T., Omori, K., 2012. A cross-system analysis of sedimentary organic carbon in the mangrove ecosystems of Xuan Thuy National Park, Vietnam. Journal of Sea Research 67, 69-76. Van Santen, P., Augustinus, P., Janssen-Stelder, B., Quartel, S., Tri, N., 2007. Sedimentation in an estuarine mangrove system. Journal of Asian Earth Sciences 29, 566-575

Maize in Vietnam: Production Systems, Constraints, and Research Priorities

Crop Production/Industries,

Optical Property and Photoelectrical Performance of a Low-bandgap Conducting Polymer Incorporated with Quantum Dots Used for Organic Solar Cells

By using spin-coating technique, a low bandgap conjugated polymer, poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopen-ta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT)  and its composite thin films have been prepared. The optical absorption and photoconductive properties with over a wide spectral range, from 350 to 950  nm, were characterized. The obtained results showed that PCPDTBT:10 wt% CdSe  composite is the most suitable for efficient light-harvesting in polymer-based photovoltaic cells. The photoelectrical conversion efficiency (PCE) of the device with  a multilayer structure of ITO/PEDOT/ PCPDTBT:CdSe /LiF/Al  reached a value as large as 1.34% with an open-circuit voltage (Voc) = 0.57 V, a short-circuit current density (Jsc) = 4.29 mA/cm2, and a fill factor (FF) = 0.27. This suggests a useful application in further fabrication of quantum dots/polymers based solar cells

A Feasibility Study in Application of a Gamma Scattering Technique for Inspecting Density Variation by Monte Carlo Method

Back-scattering gamma-rays have been extensively used for years as a nondestructive tool for inspecting the materials in different fields of the economy. The intensities of Compton scattering gamma-rays from the scattering medium strongly depend on its electron density and therefore in its mass density. This feature is very useful for using it as a viable tool for inspecting material. This work aims to investigate the feasibility of application of gamma scattering technique for inspecting density variation in some construction objects by Monte-Carlo simulation method. The gamma-ray sources of different energies and strengths have been used to  extract  the information of density variation  for  interior of  sample by  recording  the backscattering gamma-rays with a gamma-ray detector. The results of our simulations confirm that the resolution for density variation in the inspected objects is quite good. The results should also prove useful in the optimum design of the nondestructive density gauges.Back-scattering gamma-rays have been extensively used for years as a nondestructive tool for inspecting the materials in different fields of the economy. The intensities of Compton scattering gamma-rays from the scattering medium strongly depend on its electron density and therefore in its mass density. This feature is very useful for using it as a viable tool for inspecting material. This work aims to investigate the feasibility of application of gamma scattering technique for inspecting density variation in some construction objects by Monte-Carlo simulation method. The gamma-ray sources of different energies and strengths have been used to  extract  the information of density variation  for  interior of  sample by  recording  the backscattering gamma-rays with a gamma-ray detector. The results of our simulations confirm that the resolution for density variation in the inspected objects is quite good. The results should also prove useful in the optimum design of the nondestructive density gauges

Measuring citizen's satisfaction when using E-Government online public services: Lessons from Vietnam

This study aims to evaluate the factors affecting the satisfaction of citizen when using online public services through data collected from direct surveys of people. Research results show that Quality of online public services, Citizen's awareness, Privacy and security, Trust and accessibility affect citizen's satisfaction when using online public services. Based on these results, the study also gives some discussion and governance implications for researchers as well as policy-makers in improving citizen's satisfaction as well as attracting more users for online public services in Vietnam context

Theoretical predictions of melting behaviors of hcp iron up to 4000 GPa

The high-pressure melting diagram of iron is a vital ingredient for the geodynamic modeling of planetary interiors. Nonetheless, available data for molten iron show an alarming discrepancy. Herein, we propose an efficient one-phase approach to capture the solid-liquid transition of iron under extreme conditions. Our basic idea is to extend the statistical moment method to determine the density of iron in the TPa region. On that basis, we adapt the work-heat equivalence principle to appropriately link equation-of-state parameters with melting properties. This strategy allows explaining cutting-edge experimental and ab initio results without massive computational workloads. Our theoretical calculations would be helpful to constrain the chemical composition, internal dynamics, and thermal evolution of the Earth and super-Earths

CDIO-based teaching at universities: A case study for students majoring in electrical and electronic engineering technology, Vietnam

In the 1980s of the twentieth century, universities in developed countries began to realize the growing gap between the capabilities of new graduate engineers and the actual requirements of engineering branches. The strong progress of technology requires engineers to have the intellectual abilities and necessary job-specific skills to master that progress. This paper focuses on Conceive, Design, Implement and Operate (CDIO) approach-based teaching for students majoring in electrical and electronic engineering technology at engineering universities in Vietnam to demonstrate the feasibility of the teaching model. The experimental method of synthesizing qualitative and quantitative results for 90 students in control and experimental classes was used. The experimental and control classes both had 45 students. SPSS software version 22 was used to gather data and evaluate the learning results of the two experimental and control groups. According to the findings of the T-test analysis of the independent variables for the two groups, the experimental class performed better in academics and had students in the experimental group who were more satisfied with their post-test scores. This result contributes to confirm that the use of the CDIO-based teaching model in Vietnam is effective for students majoring in electrical and electronic engineering technology