PHÂN TÍCH ĐỊNH LƯỢNG CÁC CHỈ SỐ ĐA DẠNG SINH HỌC VÀ PHÂN BỐ CỦA THẢM THỰC VẬT THÂN GỖ RỪNG NGẬP MẶN VEN BIỂN MIỀN BẮC VIỆT NAM

The method of quantification of species diversity and distribution by the Shannon- Wiener Index (H’), Index of Similarity (SI), Importance Value Index (IVI), Niche width (bi), Complexity Index (CI), Spatial Distribution (Abundance/ Frequency - A/F) was used to quantify the diversity and distribution of woody true mangroves in Dong Rui, Xuan Thuy national park and Hau Loc along northern coast of Vietnam. The results showed that the species diversity and the structural complexity of the woody true mangrove vegetation at the study sites are relatively low, descending from Dong Rui (H = 1.13; CI = 12.15) to Xuan Thuy National Park (H = 0.62; CI = 11.33) and Hau Loc (H = 0.35; CI = 25.54). However the woody mangrove species compositions of the study sites are not highly different (SI ≥ 0.8). The study results also showed that B. gymnorrhiza, A. corniculatum, R. stylosa, A. marina and K. obovata are dominant species in Dong Rui (IVI = 44.36-76.50); K. obovata and A. corniculatum dominate in Xuan Thuy National Park (IVI = 115.20-148.12); K. obovata is the highly dominant species in Hau Loc (IVI = 222.92). Spatial distribution of almost studied species is continuous (A/F 0.05) indicating the habitat of the species in the study sites is relatively stable.Phương pháp đánh giá định lượng độ da dạng loài và phân bố của các loài thông qua các chỉ số đa dạng loài H, chỉ số tương đồng SI, chỉ số phức tạp CI, chỉ số giá trị quan trọng IVI, độ rộng ổ sinh thái βi và dạng phân bố không gian A/F được áp dụng để đánh giá độ đa dạng loài, dạng phân bố của một số loài cây ngập mặn thực thụ thân gỗ tại Đồng Rui, VQG Xuân Thủy và vùng ven biển huyện Hậu Lộc thuộc vùng ven biển miền Bắc Việt Nam. Kết quả nghiên cứu cho thấy độ đa dạng loài và mức độ phức tạp về cấu trúc thành phân loài cây ngập mặn thực thu thân gỗ tại các địa điểm nghiên cứu tương đối thấp, giảm dần từ Đồng Rui (H = 1,13; CI = 12,15) tới VQG Xuân Thủy (H = 0,62; CI = 11,33) và ven biển huyện Hậu Lộc (H = 0,35; CI = 25,54). Tuy nhiên thành phần loài cây ngập mặn thực thụ thân gỗ tại các địa điểm nghiên cứu có sự tương đồng khá cao (SI ≥ 0,8). Kết quả nghiên cứu cũng cho thấy Vẹt dù (B. gymnorrhiza), Sú (A. corniculatum), Đầng (R. stylosa), Mắm biển (A.  marina), Trang (K. obovata) chiếm ưu thế tại Đồng Rui (IVI = 44,36 - 76,50); Trang (K. obovata) và Sú (A. corniculatum) có mức độ ưu thế cao và lấn át manh mẽ các loài còn lại tại VQG Xuân Thủy (IVI = 115,20 - 148,12); Trang (K. obovata) là loài chiếm ưu thế tuyệt đối tại ven biển huyện Hậu Lộc và là loài lấn át mạnh mẽ các loài còn lại (IVI = 222,92). Hầu hết các loài nghiên cứu có dạng phân bố không gian liên tục (A/F 0,05), phản ảnh môi trường sống của các loài tại các địa điểm nghiên cứu tương đối ổn đinh

RELATIONSHIP BETWEEN CLIMATIC CONDITION AND MANGROVE FOREST STRUCTURE ON NORTHERN COAST OF VIETNAM

The differences in mangrove forest structure, climate, and the linear relationship between climate and mangrove forest structure on the northern coast of Vietnam were analyzed using mangrove forest data measured in 28 sample plots (Dong Rui-8, Xuan Thuy National Park-12 and Lach Sung-8) and climate data collected at the meteorological stations near the study sites (Dong Rui-Tien Yen station, Xuan Thuy National Park-Van Ly station and Lach Sung-Thanh Hoa station) in the period of 1994 - 2012. Results showed that the differences in mangrove forest structure (stem diameter, biomass and basal area) and climate (temperature and rainfall) among study sites were significant (p 0.05). Stem diameter, tree height, basal area and biomass had positive linear relationship with annual average temperature and January average temperature, and negative linear relationship with annual rainfall. A consistently low regression coefficient of less than 0.66 was found among the variables. However, all the regression models were statistically significant (p 0.05). The results could be used to develop multiple linear regression models to predict the change of mangrove ecosystems.The differences in mangrove forest structure, climate, and the linear relationship between climate and mangrove forest structure on the northern coast of Vietnam were analyzed using mangrove forest data measured in 28 sample plots (Dong Rui-8, Xuan Thuy National Park-12 and Lach Sung-8) and climate data collected at the meteorological stations near the study sites (Dong Rui-Tien Yen station, Xuan Thuy National Park-Van Ly station and Lach Sung-Thanh Hoa station) in the period of 1994 - 2012. Results showed that the differences in mangrove forest structure (stem diameter, biomass and basal area) and climate (temperature and rainfall) among study sites were significant (p 0.05). Stem diameter, tree height, basal area and biomass had positive linear relationship with annual average temperature and January average temperature, and negative linear relationship with annual rainfall. A consistently low regression coefficient of less than 0.66 was found among the variables. However, all the regression models were statistically significant (p 0.05). The results could be used to develop multiple linear regression models to predict the change of mangrove ecosystems

Educating and training labor force Under Covid 19; Impacts to Meet Market Demand in Vietnam during Globalization and Integration Era

During integration and globalization era, Vietnam labor market face challenges but also have lots of opportunities. This paper mainly use qualitative analysis with statistics, synthesis and inductive methods, combine with dialectical materialism methods. Research results indicate that because many Vietnam laborers do not have enough work skills and lack of training programs, they meet difficulties on job; hence, human resource management need to deal with issues of improving skills and knowledge for workforce to meet demand under EVFTA and Industry 4.0. There are lots of job opportunities from banking, finance to manufacturing, industries. Last but not least, this study also propose some solutions to deal with challenges in Human resources to meet demand from corporations. For instance, we need to invest more on equipment and infrastructures, as well as quality of trainers for human resources of training schools, so that Vietnam businesses can overcome challenges from EVFTA

Influence of alloying elements on the corrosion of fine art bronze in the strong corrosive environment

The influence of Sn, Zn, and Pb on the corrosion of fine art bronze in strong corrosive environment were investigated. The value of loss mass and the potential of the specimens were determined in the artificial sea-water environment. Corrosion of specimens was compared each to other to find the effect of the elements. The corrosion products were determined with the XRD/SEM/EDS analyses. The results shown that, Sn decreases the corrosion rate of the bronze alloy in marine environment while Zn increases it. The corrosion rates and potential curves showed that the corrosion rate of the bronzes reduced with immersion time. Alloy containing 0.7% Pb; 1.6% Zn; 9.7 % Sn; 88% Cu (in %wt.) has the corrosion rate as lowest. Keywords. Corrosion, strong corrosive environments, fine art bronze, Sn, Pb, Zn

Mangrove restoration in Vietnamese Mekong Delta during 2015-2020: Achievements and challenges

Mangrove forest in the Mekong Delta plays important roles in protecting coasts from soil erosion and strong waves, supplying seafood, and accumulating carbon. Despite these benefits, mangroves have been and continue to be severely damaged by the impacts of natural and socioeconomic activities. In recent years, large areas of mangrove forest have been restored through planting and other various management actions. In this study, we analyzed high-resolution WorldView-2 images to quantify changes in the mangrove forest in seven coastal provinces (Tien Giang, Ben Tre, Tra Vinh, Soc Trang, Bac Lieu, Ca Mau, and Kien Giang) of the Mekong Delta from 2015 to 2020. Our study is one of the first to analyze mangrove forest change at the commune scale, the smallest official administrative unit in Vietnam, to determine the area of restored mangroves. The potentials and challenges in future mangrove restoration were also assessed by analyzing satellite imagery and field survey data. In the study area, mangrove forest area increased by 11,184 ha (approximately 2,237 ha per year) from 79,593 ha in 2015 to 90,777 ha in 2020. A total area of 16,138 ha (approximately 20.3%) was lost due to mangrove conversion to other land uses, aquaculture activities and coastal erosion, etc., while 27,322 ha (approximately 34.1%) was restored or newly planted during state- and NGO-funded mangrove restoration projects and programs. These results confirmed that mangrove restoration projects and programs have played a significant role in maintaining and increasing mangrove forest cover in Mekong Delta. The results can also assist managers and decision makers in mangrove restoration evaluation, and suggest analyzing WorldView-2 images to monitor mangrove restoration over time in Vietnam

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam.

BACKGROUND: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. METHODS: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.    Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. CONCLUSIONS: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription

Antibiotic use and prescription and its effects on Enterobacteriaceae in the gut in children with mild respiratory infections in Ho Chi Minh City, Vietnam. A prospective observational outpatient study.

BACKGROUND AND OBJECTIVES: Treatment guidelines do not recommend antibiotic use for acute respiratory infections (ARI), except for streptococcal pharyngitis/tonsillitis and pneumonia. However, antibiotics are prescribed frequently for children with ARI, often in absence of evidence for bacterial infection. The objectives of this study were 1) to assess the appropriateness of antibiotic prescriptions for mild ARI in paediatric outpatients in relation to available guidelines and detected pathogens, 2) to assess antibiotic use on presentation using questionnaires and detection in urine 3) to assess the carriage rates and proportions of resistant intestinal Enterobacteriaceae before, during and after consultation. MATERIALS AND METHODS: Patients were prospectively enrolled in Children's Hospital 1, Ho Chi Minh City, Vietnam and diagnoses, prescribed therapy and outcome were recorded on first visit and on follow-up after 7 days. Respiratory bacterial and viral pathogens were detected using molecular assays. Antibiotic use before presentation was assessed using questionnaires and urine HPLC. The impact of antibiotic usage on intestinal Enterobacteriaceae was assessed with semi-quantitative culture on agar with and without antibiotics on presentation and after 7 and 28 days. RESULTS: A total of 563 patients were enrolled between February 2009 and February 2010. Antibiotics were prescribed for all except 2 of 563 patients. The majority were 2nd and 3rd generation oral cephalosporins and amoxicillin with or without clavulanic acid. Respiratory viruses were detected in respiratory specimens of 72.5% of patients. Antibiotic use was considered inappropriate in 90.1% and 67.5%, based on guidelines and detected pathogens, respectively. On presentation parents reported antibiotic use for 22% of patients, 41% of parents did not know and 37% denied antibiotic use. Among these three groups, six commonly used antibiotics were detected with HPLC in patients' urine in 49%, 40% and 14%, respectively. Temporary selection of 3rd generation cephalosporin resistant intestinal Enterobacteriaceae during antibiotic use was observed, with co-selection of resistance to aminoglycosides and fluoroquinolones. CONCLUSIONS: We report overuse and overprescription of antibiotics for uncomplicated ARI with selection of resistant intestinal Enterobacteriaceae, posing a risk for community transmission and persistence in a setting of a highly granular healthcare system and unrestricted access to antibiotics through private pharmacies. REGISTRATION: This study was registered at the International Standard Randomised Controlled Trials Number registry under number ISRCTN32862422: http://www.isrctn.com/ISRCTN32862422

A Multi-Center Randomised Controlled Trial of Gatifloxacin versus Azithromycin for the Treatment of Uncomplicated Typhoid Fever in Children and Adults in Vietnam

BACKGROUND: Drug resistant typhoid fever is a major clinical problem globally. Many of the first line antibiotics, including the older generation fluoroquinolones, ciprofloxacin and ofloxacin, are failing. OBJECTIVES: We performed a randomised controlled trial to compare the efficacy and safety of gatifloxacin (10 mg/kg/day) versus azithromycin (20 mg/kg/day) as a once daily oral dose for 7 days for the treatment of uncomplicated typhoid fever in children and adults in Vietnam. METHODS: An open-label multi-centre randomised trial with pre-specified per protocol analysis and intention to treat analysis was conducted. The primary outcome was fever clearance time, the secondary outcome was overall treatment failure (clinical or microbiological failure, development of typhoid fever-related complications, relapse or faecal carriage of S. typhi). PRINCIPAL FINDINGS: We enrolled 358 children and adults with suspected typhoid fever. There was no death in the study. 287 patients had blood culture confirmed typhoid fever, 145 patients received gatifloxacin and 142 patients received azithromycin. The median FCT was 106 hours in both treatment arms (95% Confidence Interval [CI]; 94-118 hours for gatifloxacin versus 88-112 hours for azithromycin), (logrank test p = 0.984, HR [95% CI] = 1.0 [0.80-1.26]). Overall treatment failure occurred in 13/145 (9%) patients in the gatifloxacin group and 13/140 (9.3%) patients in the azithromycin group, (logrank test p = 0.854, HR [95% CI] = 0.93 [0.43-2.0]). 96% (254/263) of the Salmonella enterica serovar Typhi isolates were resistant to nalidixic acid and 58% (153/263) were multidrug resistant. CONCLUSIONS: Both antibiotics showed an excellent efficacy and safety profile. Both gatifloxacin and azithromycin can be recommended for the treatment of typhoid fever particularly in regions with high rates of multidrug and nalidixic acid resistance. The cost of a 7-day treatment course of gatifloxacin is approximately one third of the cost of azithromycin in Vietnam. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN67946944

A Retrospective Analysis of the Haemodynamic and Metabolic Effects of Fluid Resuscitation in Vietnamese Adults with Severe Falciparum Malaria

BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs