105 research outputs found

    IELTS Reading: Perceived Challenges and Strategies by Vietnamese University English Majors

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    This study focused on identifying Vietnamese English as a foreign language (EFL) students’ perception of their challenges in doing the IELTS reading test and corresponding strategies to cope with these challenges. The study involved eighty-nine English majors at Can Tho University, and data were collected via a questionnaire administered to all participants and interviews conducted with 10 random students. The results showed that Vietnamese EFL students encountered a number of challenges in doing IELTS reading tests, among which lack of vocabulary and time constraint for the tests were two most noticeable difficulties. The results also revealed that the students in the study frequently employed text related, question related, and general practical strategies for doing the reading test in IELTS. Based on the findings, more opportunities to expose students to tests as well as an integration of instruction on test-taking  strategies were suggested. Keywords: EFL Vietnamese students, IELTS reading test, reading strategies, test-taking techniques DOI: 10.7176/JEP/14-28-03 Publication date:October 31st 202

    ĐẶC ĐIỂM PROTEASE NGOẠI BÀO TỪ CHỦNG Bacillus tequilensis ON1

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    A bacterial strain with casein hydrolytic activity was isolated from shrimp waste sludge from a culture pond at Phong Dien, Thua Thien Hue. Molecular identification using 16S rRNA nucleotide sequence shows a high similarity to Bacillus tequilensis on the NCBI database. Hence, the isolate was named B. tequilensis ON1. Extracellular protease activity value is 192,42 U·mL–1 after 24 h culture. Zymogram SDS-PAGE electrophoresis shows that the major extracellular protease has a molecular weight of 130 kDa. The enzyme exhibits maximal activity at 50 °C and pH 8. Protease activity increases in the presence of Ca2+ and Mg2+ ions, while Mn2+ inhibits protease activity. The protease activity was more active and stable in hydrophobic organic solvents.Từ mẫu bùn thải của ao nuôi tôm tại huyện Phong Điền, tỉnh Thừa Thiên Huế, chúng tôi đã phân lập được chủng vi khuẩn phân giải casein. Định danh phân tử thông qua giải trình tự 16S rRNA và so sánh với cơ sở dữ liệu GenBank cho thấy chủng phân lập tương đồng cao với vi khuẩn Bacillus tequilensis và được đặt tên là B. tequilensis ON1. Hoạt tính protease ngoại bào đạt giá trị cao nhất 192,42 U·mL–1 sau 24 giờ nuôi cấy. Điện di SDS-PAGE trên nền cơ chất cho thấy protease ngoại bào chính của chủng ON1 có khối lượng phân tử khoảng 130 kDa. Enzyme ngoại bào hoạt động tối ưu ở 50 °C và pH 8. Hoạt tính protease tăng lên khi có mặt Ca2+ và Mg2+, trong khi đó Mn2+ ức chế hoạt động của protease. Protease hoạt động và ổn định hơn trong các dung môi hữu cơ kỵ nước

    Aromatic hydrocarbon degradation of biofilm formed by microorganisms on cellulose material at 50 litre modules

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    Biofilms are defined as community of microorganisms which are irreversibly or reversibly attached on solid surfaces. These microorganisms are embedded in a self-produced exopolysaccharide matrix, and exhibit different growth and bioactivity compared with planktonic cells. With their high biomass density, stability, and potential for biodegradation of recalcitrant compounds contained in oil contaminated wastewater such as aromatic hydrocarbons. Aromatic hydrocarbons are the main constituents of petroleum and its refined products. These compounds are also quantitatively the main environmental pollutants worldwide. In this report, cellulose material was used as a carrier for forming biofilm by microorganisms to remove of these components. Cellulose material is considered as inexpensive, available, sustainable, little waste production and can be recycled. As a result, the microorganisms were successful to adhere on cellulose material at 50 liter module with cell density of 4.3x108 CFU/ml after 7 day-incubation. Under the scanning electron microscope with the 1500 magnification, the microbial cells had a very high density, closely linked together and firm adhesion on the cellulose material. The mixture species biofilm attached on cellulose carrier at 50 liter module had the ability to degrade 80.1, 78.3, 60.0, 98.5 and 91.2% of anthracene, fluorene, naphthalene, phenol and pyrene after 7 days, respectively. The obtained results showed that biofilm formed by multiple bacterial strains attached on cellulose material may considerably increase the degrading efficiency of aromatic hydrocarbon compounds. The results also indicated that cellulose material is suitable carrier to choose in removal of aromatic hydrocarbon contaminated wastewater. These results are considered as new approach to apply microbial films on cellulose material to degrade oil polluted waste-water in the environment

    NGHIÊN CỨU THỰC NGHIỆM TÁC DỤNG GIẢM CHẤN CỦA CÔNG TRÌNH CHỊU TẢI TRỌNG SÓNG XUNG KÍCH DƯỚI NƯỚC Ở QUẦN ĐẢO TRƯỜNG SA

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    Research on the problem of load damping of the structures under the effect of shock waves in environment generally and in water particularly is important and necessary for military structures and buildings of inhabitants. If properly designed and having solution to reduce the effects of the blast wave, general structures will be increased markedly and reduce ability of being destroyed. One of the solutions to reduce the effects of the blast wave is to glue layers of material having capable of absorbing blast waves onto the structures. The theoretical and empirical studies are currently less pronounced due to many different reasons. This paper presents modeling and experimental results from the underwater explosion topic KC09.06/11-15 in Truong Sa archipelago to determine the damping effect of the structure modeling is designed with layers of featured material on  its surface.Nghiên cứu về vấn đề giảm chấn của công trình dưới tác dụng của sóng xung kích trong các môi trường nói chung và môi trường nước nói riêng đều quan trọng và cần thiết đối với công trình quân sự và dân sinh. Nếu được thiết kế hợp lý và có các biện pháp làm giảm tác dụng của sóng nổ thì sức sống của công trình được tăng lên rõ rệt, khả năng bị phá hủy giảm. Một trong những giải pháp giảm tác dụng của sóng nổ là dán lớp vât liệu có khả năng hấp thụ sóng nổ lên kết cấu công trình. Các công trình lý thuyết và thực nghiệm về vấn đề này hiện ít được công bố do nhiều nguyên nhân khác nhau. Bài báo trình bày mô hình và kết quả thí nghiệm nổ dưới nước từ đề tài KC09.06/11-15 tại khu vực Trường Sa nhằm xác định tác dụng giảm chấn của mô hình công trình được thiết kế lớp vật liệu đặc trưng trên bề mặt

    SOME METEO - HYDRO - DYNAMICAL FEATURES IN MEKONG RIVER MOUTH AREA

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    This paper provides some meteo-hydro-dynamical features in Mekong River Mouth area which were based on statistical results from longtime measurement data such as wind, wave, sea water level, and river discharge. Study results show that distribution features of wind and wave characteristics are corresponding to seasonal variation. Predominant wind and wave directions during NE Monsoon period is NE, and in W, SW directions during SW Monsoon period. NE Monsoon period is from November to April (strongest in December and January), SW Monsoon period is from June to September (strongest in August). During NE Monsoon period the wind velocity and wave height were higher than that of SW Monsoon period. Variation of SWL at Vungtau Station shows that the tide is semi-diurnal with maximum value occurred during NE monsoon period (highest in November), and minimum value occurred during SW Monsoon period (lowest in June). Variation of river discharge is similarly at two stations (Mythuan and Cantho). During flood season (from July to December) average monthly discharge was ranged from 4,000 to 15,800 m3/s. During dry season (from January to May) average monthly discharge at both stations was less than 4,000 m3/s. Statistical data show that Mekong River Mouth area is a region of strong and complicated hydro-dynamical interaction processes between river and sea. Key words: Monsoon, North-East (NE), South-West (SW), Sea Water Level (SWL), River discharge, Mekong River

    Large-Scale Preventive Chemotherapy for the Control of Helminth Infection in Western Pacific Countries: Six Years Later

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    In 2001, Urbani and Palmer published a review of the epidemiological situation of helminthiases in the countries of the Western Pacific Region of the World Health Organization indicating the control needs in the region. Six years after this inspiring article, large-scale preventive chemotherapy for the control of helminthiasis has scaled up dramatically in the region. This paper analyzes the most recent published and unpublished country information on large-scale preventive chemotherapy and summarizes the progress made since 2000. Almost 39 million treatments were provided in 2006 in the region for the control of helminthiasis: nearly 14 million for the control of lymphatic filariasis, more than 22 million for the control of soil-transmitted helminthiasis, and over 2 million for the control of schistosomiasis. In general, control of these helminthiases is progressing well in the Mekong countries and Pacific Islands. In China, despite harboring the majority of the helminth infections of the region, the control activities have not reached the level of coverage of countries with much more limited financial resources. The control of food-borne trematodes is still limited, but pilot activities have been initiated in China, Lao People's Democratic Republic, and Vietnam

    Organic - Inorganic Hybrid Luminescent Composite for Solid-state Lighting

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    White light emitting diodes (WLEDs) made by coating organic and inorganic hybrid composites on blue LED chips. Y3Al5O12:Ce (YAG:Ce) nano inorganic powder prepared by low-temperature Sol-Gel method exhibited broad green emission with the peak at 521 nm. Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) polymer has high luminescence efficiency and red emission peak at 590 nm. The white light was obtained by mixing blue light from emission of the blue LED chip - Indium Gallium Nitride (InGaN) and green-red light from the fluorescence of nano- YAG:Ce and MEH-PPV polymer hybrid composite. The hybrid nanocomposite-based WLEDs exhibited broad band emission spectra from blue light to red wavelengths and provided the white light with a CIE-1931 coordinate of x = 0.2986, y = 0.2620 and a colour rendering index Ra = 84.36. The results suggest a potential application of nanocomposite based WLEDs in efficient solid-state lighting

    ĐẶC ĐIỂM DÒNG CHẢY VEN BỜ BẮC TRUNG BỘ (HÀ TĨNH - THỪA THIÊN-HUẾ) THỜI KỲ 4/2016

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    This paper presents the modeled results of general current pattern (daily average value) in Northern Central Vietnam Coast (Ha Tinh - Thua Thien-Hue) during April 2016. Study results show that in general, current flowed from the North to the South with small and instable velocity (V ≈ 0.1 - 0.2 m/s). From 2nd to 6th April current flowed from the South to the North. From 7th to 29th April current flowed from the North to the South. During 13rd to 16th April current velocity was weak (V ≤ 0.1 m/s). In the southern region of Thua Thien-Hue province, the direction of current was instable (from 6th to 9th and from 20th to 22nd April current flowed from the South to the North). Current distribution pattern from modeled results was in accordance with the propagation characteristics of surface water temperatures in the studied area through data analysis of satellite images.Bài báo trình bày kết quả tính toán trường dòng chảy tổng hợp trung bình ngày cho khu vực ven bờ Bắc Trung Bộ (Hà Tĩnh - Thừa Thiên-Huế) thời kỳ 4/2016. Kết quả nghiên cứu cho thấy trong thời gian nghiên cứu nhìn chung dòng chảy tổng hợp trung bình ngày có hướng từ bắc xuống nam, tốc độ tương đối nhỏ V ≈ 0,1 - 0,2 m/s và không ổn định. Từ 2-6/4/2016 dòng chảy tổng hợp trung bình ngày ven bờ có hướng từ nam lên bắc. Từ 7-29/4/2016 dòng chảy ven bờ có hướng từ bắc xuống nam. Các ngày 13-16/4/2016 dòng chảy tổng hợp trung bình ngày có tốc độ nhỏ (V ≤ 0,1 m/s). Khu vực phía nam Thừa Thiên-Huế dòng chảy tổng hợp trung bình ngày có hướng bị biến động mạnh nhất (các ngày 6-9/4 và 20-22/4 hướng dòng từ nam lên bắc). Đặc điểm phân bố dòng chảy tính toán tương đối phù hợp với đặc điểm lan truyền nhiệt độ nước tầng mặt tại khu vực nghiên cứu qua số liệu phân tích ảnh vệ tinh

    Assessment of Antioxidant and Antibacterial Activities of Lactobacillus farciminis HN11 as a Probiotic Candidate

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    Background and Objective: Lactobacillus farciminis is an obligate homofermentative bacterial species in fermented foods. Although other species such as Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus rhamnosus in Lactobacillus genus have been well characterized, probiotic characteristics of Lactobacillus farciminis still need to investigate. Thus, the objective of this study was to investigate probiotic characteristics and antibacterial activity of Lactobacillus farciminis HN11 isolated from Solanum macrocarpon sauces in Hue city, Vietnam. Material and Methods: Lactobacillus farciminis HN11 was cultured in Rogosa and Sharpe media and antibacterial activity of the free-cell suspension was assessed against Escherichia coli, Vibrio parahaemolyticus K5, Vibrio parahaemolyticus KS-02, Vibrio owensii KS-05, Vibrio alginolyticus KS-08, Vibrio alginolyticus A1-1 and Staphylococcus aureus using agar well diffusion method. Various probiotic characteristics of the isolate including antibacterial and antioxidant activities, autoaggregation and coaggregation were assessed. Furthermore, hemolytic and amino-acid dercarboxylase activities were assessed for biosafety assessment. The strain abilities to resist sodium chloride and bile salts were assessed as well. Results and Conclusion: Lactobacillus farciminis HN11 exhibited significant resistance to NaCl and bile salts. The strain expressed high coaggregation abilities for Escherichia coli, significant autoaggregation abilities and antibacterial activities against Vibrio spp. and Escherichia coli. Antioxidant assessment showed that Lactobacillus farciminis HN11 contained high antioxidant activities. This strain was negative for hemolytic and amino-acid dercarboxylase activities. Moreover, ampicillin and chloramphenicol inhibited growth of Lactobacillus farciminis HN11. This study assessed characteristics of Lactobacillus farciminis HN11 and showed its great potentials as a probiotic in fermented foods, enhancing antioxidant and decreasing harmful foodborne bacteria. Although, encapsulation of the strain within acid resistance materials is suggested to better protect it against high-acid contents of the stomach. Conflict of interest: The authors declare no conflict of interest

    EFFECT OF PRO-OXIDANT ADDITIVES ON DEGRADATION OF MULCH FILM BASED ON RECYCLED POLYETHYLENE

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    The effect of pro-oxidant additives (Iron, Cobalt and Manganese stearates) on the biodegradation of recycle polyethelene mulching films was studied in both accelerated weather and natural exposure conditions. The degradation degree of film was determined by measuring mechanical properties and scanning electronic microscope (SEM). The results showed that the mechanical properties of film samples with pro-oxirant additives decreased rapidly, and that surface film with additives was degraded clearly compared to the films without additives after 30 cycles of accelerated weather. Reliability in terms of acceleration are 28 - 30 cycles of exposure and in the natural conditions reached 10-12 months
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