Experimental Evaluation on Engineering Properties and Drying Shrinkage of No-Cement Mortar Produced by Alkaline Activation of Fly Ash-Slag Mixtures

Turning locally available industrial by-products such as fly ash (FA) and ground granulated blast-furnace slag (GGBFS) into cement-free materials has been recently received much attention from researchers. Following this trend, the present study produces alkali-activated mortars (AAFS) using a mixture of FA and GGBFS as a precursor activated by an alkaline solution of sodium hydroxide and sodium silicate. Five AAFS mixtures were prepared for the evaluation of engineering properties, drying shrinkage, and microstructural observation using various FA/GGBFS ratios of 30/70, 40/60, 50/50, 60/40, and 70/30. The experimental results show that the proportions of FA and GGBFS significantly affected the performance of the AAFS in both fresh and hardened stages. Higher GGBFS content resulted in a reduction in flowability and higher fresh unit weight. The GGBFS-rich AAFS developed its mechanical strength faster than the FA-rich AAFS and the strength gain of the GGBFS-rich AAFS was significantly higher than that of the cement-based mortar at only 1-day old, confirming the applicability of AAFS as a structural material and its potential to replace cement in the no-cement mortar production. The AAFS sample incorporating 60% of GGBFS and 40% of FA exhibited the highest strength, lowest water absorption, and less drying shrinkage with a relatively dense microstructure among the AAFS samples

Evaluation of Pseudomonas stutzeri AM1 and Pseudomonas oleovorans ST1.1 isolated from shrimp pond sediments as probiotics for whiteleg shrimp, Litopenaeus vannamei culture

This study aimed to isolate the probiotic potential of nitrifying bacterial strains and to evaluate their effects on water quality and growth performance of the whiteleg shrimp, Litopenaeus vannamei. Based on an initial screening of 100 isolates identified from sediment samples, 12 strains could remove nitrogen compounds and two strains (Pseudomonas stutzeri AM1 and P. oleovorans ST1.1) showed highly efficient nitrogen removal ability. Within 96 h, total ammonia nitrogen (TAN) removal efficiency in the two strains was 28.0-31.6% and 21.5-24.9%, respectively. The water addition of 103 CFUmL-1 of P. stutzeri AM1 (T1) and P. oleovorans ST1.1 (T2) effectively reduced TAN, nitrite, nitrate, and total sulfide and increased the survival rate and biomass of shrimp. However, no significant differences were found between the control (T0) and treatment groups (T1 and T2) in the final weight, weight gain and specific growth rate of shrimp. Overall, P. stutzeri AM1 (T1) and P. oleovorans ST1.1 used as water supplements improved water quality and the survival rate of whiteleg shrimp

POTENTIAL BENEFITS OF ARBUSCULAR MYCORRHIZA FUNGI IN SUSTAINABLE AGRICULTURAL CULTIVATION

The Arbuscular Mycorrhiza fungi have a mutualistic relationship with 80% of terrestrial plants. Arbuscular Mycorrhiza fungi are considered as a biofertilizer source because of their positive effects on plant growth and productivity They can help to reduce the amount of chemical fertilizers by up to 50% due to their ability in enhancing crops to uptake mineral nutrients efficently such as nitrogen, phosphorus, potassium, calcium, zinc. . . thereby increasing crop yield. Moreover, this endosymbiotic fungus also shows its potential as a biopesticide due to its ability to biologically antagonize a wide range of fungi, viruses, and nematodes, which cause diseases on plants. Besides, Arbuscular Mycorrhiza fungi also help plants to resist to abiotic streeses such as drought, salinity, and toxicity of heavy metals. The glomalin compound secreted by mycorrhizal fungi has the ability to bind tiny soil particles together to form a stable soil structure and aggregates, helping to improve soil qualitỵ Thus, Arbuscular Mycorrhiza fungi have a high use potential in sustainable agricultural development under the context of climate change such as drought, salinity intrusion

GRAMMATICAL ERRORS IN ACADEMIC WRITING OF ENGLISH SECOND-YEAR STUDENTS

The study aimed to analyze the common grammatical errors of students in academic writing. Mixed-method research was implemented for this study. The study team gathered 110 essays from learners in the Writing Course 4 – Social Texts classroom. Then, the researchers conducted interviews with 23 learners in order to ascertain the reasons behind their grammatical errors in writing and provide suitable remedies. Participants in this research were second-year students majoring in English Studies in the Department of English Language and Culture's High-Quality Program at a Vietnamese university. The findings revealed that the errors that made up the biggest percentage of all errors were those involving the articles (25,5 %), prepositions (14,2%), and plural/singular forms (13,7 %). On the other hand, tenses (7%), passive voice (3,8%), and subject-verb agreement (1,7%) errors had the respective lowest percentages. The results of the interviews with 23 randomly selected students in this course showed that students struggled with academic writing on a number of different levels, with the root causes being a lack of vocabulary knowledge, carelessness, and uncertainty about basic grammatical structure.  Article visualizations

Somatic embryogenesis and plant regeneration from leaf callus with genetic stability validation using SCoT markers in Paramignya trimera, a medicinal plant native to Vietnam

Xao tam phan (Paramignya trimera (Oliv.) Guillaum) is a medicinal plant native to Vietnam, that is renowned for its therapeutic properties, particularly for the treatment of various ailments, including cancer. This study investigated in vitro propagation of P. trimera through somatic embryogenesis and shoot organogenesis using leaf callus. Various culture media, plant growth regulators, malt extract, and carbon sources were evaluated to optimize callus induction and somatic embryo formation from leaf explants. DNA barcoding confirmed 96.96% to 100% homology with P. trimera specimens from Khanh Hoa province, Vietnam. The highest callus formation rate, reaching 100%, was observed in one-year-old explants cultured in Woody Plant Medium (WPM) supplemented with 2.0 mg L-1 naphthaleneacetic acid (NAA) and 0.2 mg L-1 benzylaminopurine (BAP) in the dark for over six weeks. In WPM supplemented with 30 g L-1 sucrose, 4.0 mg L-1 BAP, and 500 mg L-1 malt extract, globular stage embryos developed into embryoids and shoots and buds clumped at 10 and 18 weeks, respectively. Shoot organogenesis was observed in WPM supplemented with 30 g L-1 sucrose and 0.07 mg L-1 thidiazuron (TDZ) after 18 weeks of culture. Genetic fidelity assessments using 12 SCoT markers indicated that in vitro plantlets were homologous to the mother plant. This study provides a viable method for the conservation and sustainable cultivation of Xao tam phan, ensuring a stable supply of this valuable medicinal resource

STUDENTS’ OPINIONS ON VOCATIONAL GUIDANCE: A CASE STUDY

The problem of employment is always a crucial problem and is the concern of most parents and school students. The survey on the perception of 40 students about vocational guidance was carried out in Nguyen Viet Dung High School in Can Tho City, Vietnam. Results show that students are very concerned about their future career; students have a proper perception of vocational guidance and recognize well factors which affect their career choice.  Article visualizations

PERSPECTIVES ON PERCEPTIONS AND PRACTICE THROUGH LEARNING CULTURES OF ENGLISH-SPEAKING COUNTRIES OF HIGH-QUALITY ENGLISH STUDIES PROGRAM STUDENTS, SCHOOL OF FOREIGN LANGUAGES, CAN THO UNIVERSITY, VIETNAM

The overall goal of the project is to understand the awareness or perceptions and practice of students of the High-quality English Studies program, School of Foreign Languages (SFL), Can Tho University (CTU), Vietnam when studying cultures of English-speaking countries (CESCs) to improve intercultural competence. The research on the perspectives or opinions of 200 High-quality English Studies students, 12 of them joining the semi-structured interview, about their awareness and practice through learning CESCs. The analysis would help the researcher understand the difficulties of students when studying cultural modules from English-speaking countries at SFL, CTU. The research results would suggest solutions to overcome the difficulties that students encounter, and at the same time provide factors that contribute to improving the intercultural competence of language students. Also, through the research results, despite many obstacles in the process of absorbing culture from cultural modules, students still retain their interest and love for the course-CESCs. However, it can be seen that the difficulty that many students often encounter is still cultural differences, thereby raising awareness of the need to learn cultures for students. Next is to design teaching materials to become more attractive and attractive, proactively find opportunities to communicate with foreigners.  Article visualizations