ALMA OBSERVATIONS OF W HYDRAE: IMPACT OF MISSING BASELINES

Do Thi Hoai,Tuan-Anh Pham,Pham Tuyet Nhung,Pierre Darriulat,Pham Ngoc Diep,Nguyen Bich Ngoc,Tran Thi Thai 한국천문학회 2021 Journal of The Korean Astronomical Society Vol.54 No.6

The lack of short baselines, referred to as the short-spacing problem (SSP), is a well-known limitation of the performance of radio interferometers, causing a reduction of the flux detected from source structure on large angular scales. The very large number of antennas operated in the Atacama Large Millimeter/sub-millimeter Array (ALMA) generates situations for which the impact of the SSP takes a complex form, not simply measurable by a single number, such as the maximal recoverable scale. In particular, extended antenna configurations, complemented by a small group of closeby antennas at the centre of the array, may result in a double-humped baseline distribution with a significant gap between the two groups. In such cases one should adopt as the effective maximal recoverable scale the one associated with the extended array and use only the central array to recover missing ux, as one would do with single dish or ACA (Atacama Compact Array) observations. The impact of the missing baselines can be very important and may easily be underestimated, or even overlooked. The present study uses ALMA archival data of the ^{29}SiO(8-7) line emission of the AGB star W Hydrae for a demonstration. A critical discussion of the reliability of the observations away from the star is presented together with comments of a broader scope. Properties of the circumstellar envelope of W Hya within ~15 au from the star, many of which are not mentioned in the published literature, are briefly described and compared with R Doradus, an AGB star having properties very similar to W Hya.

Impacts of Climate Change and Financial Support on Household Livelihoods: Evidence from the Northwest Sub-Region of Vietnam

DO, Thi Thu Hien,NGUYEN, Thi Lan Anh,NGUYEN, Thi Hoai Phuong Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.6

The study's goal is to determine the amount of climate change's impact on ethnic minority (EM) households' livelihoods, as well as their adaptability to climate change and long-term viability. The research was conducted in Vietnam's Northwestern Sub-region, where ethnic minorities account for more than half of the overall population. The study uses a combination of qualitative and quantitative methods based on a survey of 480 households in 04 provinces severely affected by climate change in the Northwest sub-region of Vietnam. The results show that: climate change (extreme weather events) occurs with increasing frequency, mainly affecting the life expectancy, health, and capital of households; Vulnerable groups (women, ethnic minorities) have a poor adaptive capacity and mainly suffer the consequences of shocks, are afraid to change their livelihoods; Microfinance plays an important role in enhancing the sustainability of livelihoods through increasing capital and financial assets and reducing the vulnerability of ethnic minority households. Finally, research has some solutions for microfinance - special credit specifically for ethnic minority households in the Northwest Sub-region: support for microfinance advice, home credit with transition orientations to adapt to climate change response and relieves its impact on the social lives.

Isolation, characterization and neutralizing activity of porcine epidemic diarrhea viruses from Vietnam

Do, Van Tan,Truong, Quang Lam,Dao, Hoai Thu,Nguyen, Thi Lan,Kim, Jini,Hahn, Tae-Wook The Korean Society of Veterinary Science 2021 大韓獸醫學會誌 Vol.61 No.3

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were successfully propagated in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene revealed that all 3 isolates belong to genogroup 2a, which is closely related to other prevalent Asian strains. Amino acid sequence comparisons revealed 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) evolve continuously. Experiments in animals demonstrated that antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibody against the homologous strain, and showed a relatively lower level of neutralizing antibody against the field isolates. This finding would be helpful in choosing a PEDV strain for vaccine development.

Temperature-Dependent Photoluminescence and Absoprtion of CdSe Quantum dots Embedded in PMMA

Tran Thi Kim Chi,Ung Thi Dieu Thuy,Nguyen Quang Liem,Man Hoai Nam,Do Xuan Thanh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Photoluminescence and absorption studies of CdSe quantum dots in polymethylmethacrylate (PMMA) were carried out in the temperature range 14 - 310 K. We found an anomalously discontinuous variation of the photoluminescence intensity and the peak position around 50 K. Two different kinds of states, whose populations are temperature-dependent, are proposed as the origins for the emissions at lower and higher temperatures. The absorption exhibited a temperature-dependent behavior similar to that of the photoluminescence.O Photoluminescence and absorption studies of CdSe quantum dots in polymethylmethacrylate (PMMA) were carried out in the temperature range 14 - 310 K. We found an anomalously discontinuous variation of the photoluminescence intensity and the peak position around 50 K. Two different kinds of states, whose populations are temperature-dependent, are proposed as the origins for the emissions at lower and higher temperatures. The absorption exhibited a temperature-dependent behavior similar to that of the photoluminescence.O

Porcine epidemic diarrhea viruses from Vietnam: isolation, characterization, and neutralizing activity

Van Tan Do,Quang Lam Truong,Hoai Thu Dao,Thi Lan Nguyen,Minna Shin,Kyeong Ryeol Shin,Tae-Wook Hahn 대한수의학회 2023 大韓獸醫學會誌 Vol.63 No.2

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death, with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were propagated successfully in Vero cells at high virus titers. Sequence analysis of the fulllength spike (S) gene showed that all 3 isolates belong to genogroup 2b, which is closely related to other prevalent Asian strains. A comparison of the amino acid sequence revealed a 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013–2015, suggesting that field PED viruses (PEDVs) are evolving continuously. Experiments in animals showed that the antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log2) of neutralizing antibodies against the homologous strain and a relatively moderate level of neutralizing antibodies against the field isolates. This finding would be helpful in selecting a PEDV strain for vaccine development.

Retraction: Isolation, characterization and neutralizing activity of porcine epidemic diarrhea viruses from Vietnam

Van Tan Do,Quang Lam Truong,Hoai Thu Dao,Thi Lan Nguyen,Jini Kim,Tae-Wook Hahn 대한수의학회 2023 大韓獸醫學會誌 Vol.63 No.1

Three isolates (HID9047, HID9048, and HID9049) were listed in the original text as belonging to subgroup 2a during phylogenetic analysis. However, it was later determined by adding PEDV reference strains that they actually belonged to subgroup 2b. Therefore, we retract the former article

One-Pot Preparation of Antibacterial Electrospun Polycaprolactone Membrane Embedded with Gamma Irradiation-Induced Silver Nanoparticles

Chien Minh Tran,Ngoc Thi‑Thanh Nguyen,Minh Hieu Ho,Vinh Khanh Doan,Khanh Loan Ly,Nhi Ngoc‑Thao Dang,Nam Minh‑Phuong Tran,Hoai Thi‑Thu Nguyen,Long Phuoc Truong,Thai Minh Do,Quyen Ngoc Tran,Hien Quoc Ng 한국섬유공학회 2023 Fibers and polymers Vol.24 No.1

In this study, we proposed a straightforward electrospun polycaprolactone (PCL) loaded with silver nanoparticles (SNPs)membrane fabrication process, in which SNPs were directly synthesized from silver nitrate (AgNO3) in PCL–acetone mixtureby gamma irradiation. The insolubility of AgNO3in PCL solution was solved using an auxiliary dimethyl sulfoxide solvent. As a physical approach, gamma rays readily converted silver ions into SNPs without the addition of harmful reductionagents, which reduced the cytotoxicity of the synthesized material. By avoiding some processes such as purification, solventremoval, or redispersion of SNPs, this method was more time-saving compared to other related studies. SNPs formation wasconfirmed by both UV–Visible spectrum (UV–Vis) and X-ray diffraction analysis. Scanning electron microscopy (SEM)revealed that the addition of SNPs significantly reduced the fiber diameter of PCL–Ag membranes compared to that of rawPCL. Uniform spherical-shaped SNPs incorporated in PCL fibers were observed under transmission electron microscopy(TEM). The tensile test showed that the electrospun PCL–Ag membranes exhibited good mechanical characteristics. Moistureeasily penetrated the porous microstructure of PCL–Ag, facilitating wound humidity regulation. Inductively coupledplasma-mass spectroscopy (ICP-MS) was employed to study the release profiles of SNPs at different time intervals. Overall,the PCL–Ag 500 ppm sample exerted excellent antibacterial activity against Pseudomonas aeruginosa and Staphylococcusaureus strains and low in vitro cytotoxicity.

Determinants of Operational Self-Sustainability of Microfinance Institutions in Vietnam

LE, Thanh Tam,DAO, Lan Phuong,DO, Ngoc Mai,TRUONG, Thi Hoai Linh,NGUYEN, Thi Thuy Duong,TRAN, Chung Thuy Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

The purpose of this paper is to investigate the determinants of the Operational Self-Sustainability (OSS) of Vietnamese microfinance institutions (MFIs). This research uses both qualitative and quantitative research methods: (i) qualitative research was via in-depth interviews with ten microfinance practitioners, policymakers and researchers; (ii) quantitative research was conducted by using panel data of 34 MFIs in the period 2011-2015 with binary logistics and OLS regressions. Results are as follows: (i) MFIs' OSS in Vietnam are mainly determined by five key factors: portfolio at risk (PAR>30), capital structure, gross loan portfolio, scope of activities and legal form; (ii) OSS are most affected by legal status (social organizations have better OSS than formal MFIs or programs/projects), location (MFIs focus in one province have higher OSS than working nationwide or just in one district), capital structure (MFIs with more equity proportion have higher OSS); (iii) surprisingly, average loan size per borrower and age of MFIs do not have statistically significant correlation with OSS. The key recommendations are: (i) MFIs should focus on its professionality and increase its equity; (ii) related stakeholders such as State Bank of Vietnam should promote the enabling ecosystem for microfinance development to enhance poverty reduction and economic development.