A model of mother tongue-based bilingual education in Vietnam: Achievements and lessons learnt

This articlesummarizes findings from the implementation of the mother tongue-based bilingual education model and the tracer study on the students who participated in the mother tongue-based bilingual education program at preschool and primary schools and transitioned to higher levels of education in the framework of the UNICEFfunded "Learning for children" project. The research team would like to thank UNICEF Viet Nam,the Vietnam National Institute of Educational Sciences, Departments of Education and Training of Lao Cai, Gia Lai and Tra Vinh provinces, and educational managers, teachers and students in the three provinces for their support and cooperation.Education practices in ethnic minority areas in Vietnam with regional and ethnic differences influence its educational development. In particular, the language difference is a factor because the language used in teaching and learning is Vietnamese, not the mother tongue. Therefore, the mother tonguebased bilingual education model was developed to provide quick and convenient access to Vietnamese (the nation’s official language) and knowledge for students in ethnic minority areas. Its approach is to use the ethnic students’ mother tongues as the initial foundation in their first schooling years. The outstanding results of the successfully tested model have contributed to the improvement of the quality of ethnic minority education in Vietnam

KẾT QUẢ BƯỚC ĐẦU NGHIÊN CỨU TỐC ĐỘ LẮNG ĐỌNG, NGUỒN TRẦM TÍCH ĐÁY VỊNH HẠ LONG: DẤU HIỆU TỪ KHOÁNG VẬT SÉT, ĐỒNG VỊ 210Pb VÀ 137Cs

Ha Long bay is the World Natural Heritage, which annaually attracts a lot of foreign and domestic tourists. Nevertheless, in recent years, the landscape of Ha Long bay is devastated by many negative impacts-the shallowing of the bottom of bay is one of the great negative impacts. How is the shallowing of the bottom of Ha Long bay? What are reasons for the negative impacts? Based on the approach “source-to-sink” combined with results of clay mineral contents, results of 210Pb and 137Cs radionuclides, this study will contribute to clarifying the shallowing of the bottom of Ha Long bay. Results of smectite, illite and smectite/(illite+chlorite) ratios indicated that the sediment in Ha Long bay not only derives from the surrounding region of Ha Long bay but also derives from Red river system. Results of 210Pbex and 137Csex revealed the sedimentation rates in the Ha Long bay have varied between 0.47 - 0.75 cm/year over the last 100 years. It can be divided into four periods: period I (1920 - 1930); period II (1930 - 1960); period III (1960 - 1990); and period IV (1990 - 2011) with the average rate of 0.45 cm/year; 0.66 cm/year; 0.50 cm/year; and 0.85 cm/year respectively. The shallowing of the bottom of Ha Long bay was impacted by human activities such as building reservoirs, mining, urbanization or aquaculture etc.Vịnh Hạ Long là một trong những di sản thiên nhiên thế giới, hàng năm, vịnh thu hút nhiều du khách trong và ngoài nước. Tuy nhiên, trong những năm gần đây, cảnh quan vịnh bị tác động bởi hàng loạt các tác động tiêu cực - bồi lắng đáy vịnh là một trong những tác động tiêu cực lớn. Đáy vịnh Hạ Long bồi cạn ra sao? nguyên nhân nào gây ra? Theo cách tiếp cận từ nguồn cung cấp đến bồn lắng đọng trầm tích “source-to-sink” và phối hợp với kết quả thành phần khoáng vật sét và đồng vị phóng xạ 210Pb và 137Cs, nghiên cứu này sẽ góp phần là sáng tỏ vấn đề trên. Kết quả hàm lượng smectite, illite và chỉ số smectite/( illite+chlorite) chỉ thị: trầm tích chuyển vào vịnh Hạ Long không chỉ nhận từ vùng xung quanh vịnh mà nó còn nhận từ hệ thống sông Hồng. Kết quả 210Pb và 137Cs cho thấy: tốc độ lắng đọng trầm tích tại vịnh Hạ Long trong vòng 100 năm qua, dao động trong khoảng 0,47 - 0,75 cm/năm, và có thể chia làm 4 giai đoạn: giai đoạn I (từ năm 1920 - 1930), giai đoạn II (từ năm 1930 - 1960); giai đoạn III (1960 - 1990) và giai đoạn IV (từ năm 1990 - 2011) với tốc độ lắng đọng trung bình lần lượt là 0,45 cm/năm; 0,66 cm/năm; 0,50 cm/năm; và 0,85 cm/năm tương ứng. Các hoạt động của con người như: xây hồ chứa, khai thác mỏ, đô thị hóa, nuôi trồng thủy sản ... là nguyên nhân gây bồi cạn đáy vịnh

A modified Sequential Organ Failure Assessment score for dengue: development, evaluation and proposal for use in clinical trials

Background Dengue is a neglected tropical disease, for which no therapeutic agents have shown clinical efficacy to date. Clinical trials have used strikingly variable clinical endpoints, which hampers reproducibility and comparability of findings. We investigated a delta modified Sequential Organ Failure Assessment (delta mSOFA) score as a uniform composite clinical endpoint for use in clinical trials investigating therapeutics for moderate and severe dengue. Methods We developed a modified SOFA score for dengue, measured and evaluated its performance at baseline and 48 h after enrolment in a prospective observational cohort of 124 adults admitted to a tertiary referral hospital in Vietnam with dengue shock. The modified SOFA score included pulse pressure in the cardiovascular component. Binary logistic regression, cox proportional hazard and linear regression models were used to estimate association between mSOFA, delta mSOFA and clinical outcomes. Results The analysis included 124 adults with dengue shock. 29 (23.4%) patients required ICU admission for organ support or due to persistent haemodynamic instability: 9/124 (7.3%) required mechanical ventilation, 8/124 (6.5%) required vasopressors, 6/124 (4.8%) required haemofiltration and 5/124 (4.0%) patients died. In univariate analyses, higher baseline and delta (48 h) mSOFA score for dengue were associated with admission to ICU, requirement for organ support and mortality, duration of ICU and hospital admission and IV fluid use. Conclusions The baseline and delta mSOFA scores for dengue performed well to discriminate patients with dengue shock by clinical outcomes, including duration of ICU and hospital admission, requirement for organ support and death. We plan to use delta mSOFA as the primary endpoint in an upcoming host-directed therapeutic trial and investigate the performance of this score in other phenotypes of severe dengue in adults and children

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Experimental Study on Impact of Thermal-Assisted Machining on SKD11 Steel Machinability

Machining in a heated environment has been used in pressure machining and metal cutting. Thermal-assisted machining is a new machining method performed on conventional machine tools, CNC machines, in which the workpiece is heated before machining. Different heat sources do the thermal-assisted: electrical energy, laser beam, magnetic induction. However, there is very little research on thermal-assisted machining when milling SKD11 steel, a difficult-in-processing material but widely used in the industry. Material machinability refers to the ability of material machining that is difficult or easy. Material machinability is measured by tool life, material removal ability, shear force, cutting vibration, surface roughness. The material's machinability is directly influenced by its microscopic structure and is related to the cutting mode. This paper has highlighted the study of material machinability when thermal-assisted machining and compared to the conventional one. This study also highlights the crucial role in assessing the effect of heating on the SKD11 steel machinability. This study analyzed the technological parameters' role on the shear force, chip shrinkage, surface roughness, and shear vibrations during normal machining and SKD11 steel heating. The study results showed that the material's microstructure and the amplitude of vibration did not change under the heating process's effect with a temperature range of 200oC - 400oC. However, the shearing force during heat processing is drastically reduced compared to conventional machining. Chip shrinkage increased by 31.7% when heated to 400oC, while roughness decreased by 47.1%

Ultrasound-Assisted Enzymatic Extraction of Adenosine from Vietnamese Cordyceps militaris and Bioactivity Analysis of the Extract

Vietnamese Cordyceps militaris (C. militaris) has long been recognized as one of the most valuable traditional Chinese medicines. In this study, adenosine was extracted from Vietnamese C. militaris by ultrasound-assisted enzymatic extraction method (UAEE) using water as a solvent. Then, the effects of five single factors on adenosine content including pH, enzyme-to-material ratio, ultrasonic power, ultrasonic time, and ultrasonic temperature were determined. After that, three factors consisting of ultrasonic power, ultrasonic time, and ultrasonic temperature were chosen based on their effects on adenosine content. The simultaneous influence of these factors on the adenosine content was investigated by response surface method using central composite design. The adenosine content was evaluated by high-performance liquid chromatography method. Under the optimal conditions, the extract was evaluated for antioxidant and anticancer bioactivities. In addition, different extraction methods including aqueous extraction (AE), ultrasound-assisted extraction (UAE), and enzyme-assisted extraction (EAE) methods were carried out to compare with UAEE. As a result, it can be concluded that UAEE is a promising method for adenosine extraction and further studies regarding isolation and purification need to be conducted

Emission reduction opportunities in a rapidly growing economy:\ua0a case study of Ho Chi Minh City

Vietnam’s Green Growth Action Plan for the period 2014–2020 sets out an overall plan for the sustainable development of the country. One of the cornerstones of that plan is the development of a greenhouse gas inventory and emission reduction opportunity assessment for Ho Chi Minh City. This provides a basis for the roadmap towards green growth in Ho Chi Minh City, one of Vietnam’s largest cities. Marginal costs of 38 emission reduction measures were determined for two main economy sectors, namely energy (32 measures) and agriculture, forestry, and other land use (6 measures). From that analysis, a marginal abatement cost curve was compiled for the energy sector. The total emission reduction opportunities available in 2020 are estimated to be 8.97 million tCO2e, which represents a 14.7% reduction compared to business as usual. Even when the city only implements reduction measures with negative marginal costs (i.e., abatement that saves money), significant reductions of 5.25 MtCO2e (8.6% reduction compared to business as usual) would be achieved. There are significant similarities in abatement opportunities between Ho Chi Minh City and Hanoi, Vietnam’s capital. The case study shows significant reduction in greenhouse gas emissions can be achieved in fast-growing cities with an appropriate level of investment and government support

Supercritical Fluid Extraction of Polyphenols from Vietnamese Callisia fragrans Leaves and Antioxidant Activity of the Extract

Vietnamese Callisia fragrans (C. fragrans) has been considered as a valuable traditional plant with various medicinal properties. In this study, polyphenols were extracted from Vietnamese C. fragrans leaves by supercritical carbon dioxide (SC-CO2) extraction method using ethanol as a cosolvent. The investigation of four factors influencing the total polyphenol content (TPC) and antioxidant activity of the extracts obtained from each single-factor experiment was conducted including ethanol concentration, CO2 flow rate, extraction temperature, and pressure. Besides, the extraction efficiency of the SC-CO2 method under the best extraction conditions, namely ethanol concentration of 14%, CO2 flow rate of 20 g/min, extraction temperature of 45°C, and pressure of 200 bar was compared to that of the Soxhlet extraction (SE) method in terms of the TPC and antioxidant activity of the extracts. The results showed that using SC-CO2 method, the TPC and the half-maximal inhibitory concentration value obtained were of 87.42 ± 1.33 mg/g and 243.83 ± 5.30 μM TE/g, respectively, with much less time and solvent amount required while that obtained using SE method were of 85.34 ± 4.27 mg/g and 236.33 ± 7.66 μM TE/g, respectively. This indicated that SC-CO2 would be suitable for the industrial production of polyphenols with high antioxidant activity of the extracts obtained due to the restrictions of using the SE method and advantages of applying SC-CO2 method. Therefore, SC-CO2 method could be regarded as a potentially upcoming extraction technique which might be employed to replace the conventional SE method

Utilization of Response Surface Methodology in Optimization of Polysaccharides Extraction from Vietnamese Red Ganoderma lucidum by Ultrasound-Assisted Enzymatic Method and Examination of Bioactivities of the Extract

Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese traditional remedies due to its potential value for health. In this study, polysaccharides were extracted from G. lucidum using ultrasound-assisted enzymatic extraction method. The response surface methodology and Box–Behnken design were employed to investigate the effects of pH, extraction temperature, extraction time, and ultrasonic power on the content of polysaccharides. Based on ultraviolet-visible spectroscopy analysis, the highest content of polysaccharides in the extract was 32.08 mg/g under optimum experimental parameters including enzyme concentration of 3%, pH of 5.5, extraction temperature of 45°C, extraction time of 30 min, and ultrasonic power of 480 W. The Fourier-transform infrared spectroscopy was also used to identify the functional groups in the extracts. The molecular weights of polysaccharides were determined by gel permeation chromatography. The obtained extract was then evaluated for anticancer activities by using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, showing the anticancer activities with the half-maximal inhibitory concentration value of more than 512 μg/mL. This result suggested that UAEE could be considered as an appropriate and effective extraction method for bioactive crude polysaccharides from G. lucidum