THE IMPACT OF QUESTIONING AND SEMANTIC MAP IN PRE-READING STAGE ON STUDENTS' READING COMPREHENSION: A COMPARATIVE STUDY

Pre-reading activities play an important role in language reading classrooms since they help to activate students’ background knowledge of the topics being taught, which results in improving students’ reading comprehension. Most studies in the literature focus on exploring the effects of individual pre-reading activities such as brainstorming, pre-teaching vocabulary, questioning on students’ performance in doing comprehension tasks. Few studies have been conducted to explore whether one technique is better than the others in activating students’ schemata in reading lessons. The current study investigates the impact of Questioning and Semantic map in Pre-reading stage on EFL gifted high school students’ reading comprehension. The participants were 52 gifted students from two science classes for twelfth graders (they were non gifted English students). They shared the same culture, native language, educational background and age. The data were collected through two reading proficiency tests (pre-test and post-test) and individual interviews. The findings revealed that both Questioning and Semantic map had positive impacts on gifted students’ reading comprehension. Especially, the students who received Semantic treatment had significantly better improvement in their reading skill. The findings shed lights on what can be done to improve EFL students’ reading performance.  Article visualizations

AN INVESTIGATION INTO THE USE OF COLLOCATIONS IN ACADEMIC ESSAYS OF ENGLISH-MAJORED STUDENTS OF THE HIGH-QUALITY PROGRAM AT CAN THO UNIVERSITY, VIETNAM

One of the main goals of language learners is to master all four skills of listening, speaking, reading and writing when it comes to their acquisition of the target language. However, during the process of learning English, learners inevitably face a variety of challenges related to their writing including grammatical errors, word choice, organization, idea development, and most importantly their difficulties in using collocations (Duong & Nguyen, 2021). Therefore, this study has been conducted to investigate the students’ use of English collocations in their academic essays associated with their difficulties so that appropriate pedagogical approaches and practices would be taken into consideration in order to help students improve their English collocational competences in academic writing. This descriptive study was carried out with 103 English-majored students of the High-quality program of the School of Foreign Languages at Can Tho University, Vietnam. A 5-point Likert scale survey with 18 questionnaire items was employed to examine the frequency of students' exposure to as well as their usage of English collocations, and their difficulties in using English collocations. The results of this study have shown that the most commonly used collocations in the students’ academic essays were ‘verb + noun’, and ‘adjective + noun’ lexical collocations. Additionally, the research outcomes have revealed that the types of English collocations that the students were more likely to make the most mistakes belonged to ‘verb + adverb’, and ‘adjective + noun’ lexical collocations.  Article visualizations

SEASONAL VARIATION OF PHYTOPLANKTON FUNCTIONAL GROUPS IN TUYEN LAM RESERVOIR, CENTRAL HIGHLANDS, VIETNAM

Seasonal changes in freshwater phytoplankton assemblages at Tuyen Lam Reservoir in the Central Highlands of Vietnam were classified into 23 functional groups based on physiological, morphological, and ecological characteristics. A total of 168 species were recorded during 10 surveys from 2015 to 2019 at 7 sampling sites, with Chlorophyta dominating in number of species. Phytoplankton abundance varied from 0.18×105 to 21.2×105 cells/L during the study period, mainly due to cyanobacteria. Seven of the 23 functional groups were considered to be dominant (relative density > 5%).  The dominant functional groups were groups M and G in the dry season and groups M, G, P, and E in the rainy season. Group M (Microcystis aeruginosa) was the most common in both seasons, while group P (Closterium, Staurastrum, Aulacoseira), group E (Dinobryon, Synura), and group G (Sphaerocystis, Eudorina) were more common in the rainy season. The Shannon diversity index (H¢) showed that phytoplankton communities were relatively diverse and that most of the study sites were lightly polluted. However, the ecological status has deteriorated at some locations due to the overgrowth of group M, leading to eutrophication in this reservoir. This study highlights the usefulness of functional groups in the study of seasonal changes in phytoplankton dynamics. Functional groups are applied for the first time at Tuyen Lam Reservoir and can be used to predict early-stage cyanobacterial blooms in future studies

Characterization of O-glycan binding lectin from the red alga Hydropuntia eucheumatoides

The red alga, Hydropuntia eucheumatoides is one of the algal genera from which agar is commercially extracted, and is the main source of agar in the world. The lectin HEL from the red alga H. eucheumatoides was isolated by a combination of aqueous ethanol extraction, ethanol precipitation, ion exchange and filtration chromatography. Lectin gave a single band with molecular mass of 17,000 Da in both non-reducing and reducing SDS-PAGE conditions, therefore lectin exists in monomeric form. The hemagglutination activities of HEL were stable over a wide range of pH from 3 to 10, temperature up 60 oC and not affected by either the presence of EDTA or addition of divalent cations, indicating that lectin requires no metal for biological activity. The hemagglutination activities of HEL were not inhibited by monosaccharides and glycoproteins, D-glucose, D-mannose, D-galactose, D-xylose, N-acety-D-mannosamine, transferin, fetuin and yeast mannan, but strongly inhibited by monosaccharides containing  acetamido groups at equatorial C2 position, such as N-acetyl-galactosamine, N-acetyl-glucosamine, N-acetyl-neuraminic acid and glycoprotein porcine stomach mucin bearing O-glycans. Thus, lectin is specific for O-glycans and  may recognize the sequences GalNAcαSer/Thr, GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc(β1-3)GalNAc- and GluNAc(α1-4)Gal- under interacting with the acetamido groups at equatorial C2 position of the terminal sugar residues in oligosaccharide structures of O-glycans. The red alga H. eucheumatoides could promise to be a source of valuable lectins for application in biochemistry and biomedicine

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

IDENTIFICATION AND CHARACTERIZATION OF A PURPLE NONSULFUR BACTERIUM ISOLATED FROM COASTAL AREA OF HAI PHONG FOR USING IN PRODUCTION OF UNSATURATED FATTY ACID (OMEGA 6, 7, 9)

Purple nonsulfur bacteria are a group that has so much biotechnological applications, particularly in producing of functional food rich with unsaturated fatty acids. A purple nonsulfur bacterium (named HPB.6) was chosen based on its strong growth, high lipid and synthesis of unsaturated fatty acid (omega 6,7,9). Studying on basic biological characteristics showed that the cells of HPB.6 were observed as ovoid-rod shape, none motility, Gram negative staining. The diameter of single bacterium was about 0.8-1.0 µm. The cells divide by binary fission and had bacteriochlorophyll a (Bchl a). This bacterium grew well on medium with carbon and nitrogen sources such as acetate, succinate, pyruvate, butyrate, glutamate, arginine, leucine, tyrosine, alanine, methionine, threonine, glutamine, yeast extract and NH4Cl. This selected strain grew well on medium with salt concentrations from 1.5 - 6.0% (optimum 3%), pH from 5.0 to 8.0 (optimum at pH 6.5) and could withstand Na2S at 4.0 - 5.2 mM. Based on morphological, physiological properties and 16S rRNA analysis received demonstrated that HPB.6 strain belongs to the species Rhodovulum sulfidophilum

A propensity score matching analysis of the relationship between forest resources and household welfare in Vietnam

Using secondary data from a socio-economic quantitative household survey in of the North Central region of Vietnam, the main aim of our study is to analyze the causal effect of forest resources on household income and poverty. Based on the observed characteristics of a forest-based livelihood and forest-related activities, we use a propensity score matching (PSM) method to control for potential bias arising from self-selection. The PSM results indicate that households with a forest livelihood had a higher level of income and lower level of poverty than did those without. Interestingly, our findings confirm that a forest-based livelihood offers much higher income than any other type of livelihood adopted by local households. Also, the poverty rate among households with a forest livelihood is lower than those earning non-labor income or engaged in wage/crop and crop livelihoods. Moreover, households whose livelihoods depend on timber forest products (TFPs) and animals (non-TFPs) also had higher income and lower levels of poverty than did those lacking these resources. Among households and provinces, we find differing opportunities deriving from forest resources, suggesting that there are potential barriers hindering local households from pursuing a forest livelihood or participating in some forest activities. Therefore, government policy and regulations on forest management should focus on improving the access of households to forest resources, at the same time enhancing the sustainability of these resources

Multi-correlation between nematode communities and environmental variables in mangrove-shrimp ponds, Ca Mau Province, Southern Vietnam

Multi-correlation between bio-indices of nematode communities and ecological parameters in mangrove-shrimp farming ponds in Tam Giang commune, Nam Can District, Ca Mau Province, Vietnam were investigated. In which, diversities of nematode communities and several environmental variables in eight ponds were considered to process. Our findings underlined the high diversity of nematode communities in mangrove-shrimp farming ponds compared to other mangrove habitats. Nematode diversities provided more oppotunity in natural food for shrimp. Single correlation analyses showed that the species richness index correlated significantly to three variables (salinity, total organic carbon, and total nitrogen), the Margalef diversity index correlated to two variables (salinity, total organic carbon), and the expected number of species for 50 individuals index correlated with one variable (salinity). Results of multi-correlation analyses between the nematode bio-indices and the environmental variables were completely different from those of single-correlation analyses. In multi-correlation analyses, the species richness and the Margalef diversity index correlated to two variables (salinity, total organic carbon), Pielou’s evenness index and Hill indices correlated with dissolved oxygen, also the Hurlbert index correlated to total organic carbon. Hence, it is necessary to pay attention to the impact of complex interactions between the multi-environmental variables and nematode communities. This research aims to explain the differences between single- and multi-correlation for evaluation of the effects of environmental factors on nematodes as well as aquatic organisms.

A propensity score matching analysis of the relationship between forest resources and household welfare in Vietnam

Using secondary data from a socio-economic quantitative household survey in of the North Central region of Vietnam, the main aim of our study is to analyze the causal effect of forest resources on household income and poverty. Based on the observed characteristics of a forest-based livelihood and forest-related activities, we use a propensity score matching (PSM) method to control for potential bias arising from self-selection. The PSM results indicate that households with a forest livelihood had a higher level of income and lower level of poverty than did those without. Interestingly, our findings confirm that a forest-based livelihood offers much higher income than any other type of livelihood adopted by local households. Also, the poverty rate among households with a forest livelihood is lower than those earning non-labor income or engaged in wage/crop and crop livelihoods. Moreover, households whose livelihoods depend on timber forest products (TFPs) and animals (non-TFPs) also had higher income and lower levels of poverty than did those lacking these resources. Among households and provinces, we find differing opportunities deriving from forest resources, suggesting that there are potential barriers hindering local households from pursuing a forest livelihood or participating in some forest activities. Therefore, government policy and regulations on forest management should focus on improving the access of households to forest resources, at the same time enhancing the sustainability of these resources

Study on anticorrosion properties of epoxy primers on steel.

Epoxy resin DER 671X75 was reinforced by nanoclay cloisite 30B with content of 2% and primer coatings based on epoxy resin DER 671X75 were formed with pigments, fillers. Epoxy coating  films were exposed by electrochemical method in NaCl 3.5 % solution in 28 days and salt spray accelerated tester in 330 hrs. The results show that nanoclay cloisite 30B are improved anticorrosion properties of primer coatings based on epoxy resin DER671X75. Keywords. Epoxy primer coating, nanoclay cloisite 30B, epoxy resin DER 671X75, electrochemical, anticorrosion properties steel