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The study was conducted to (i) isolate, select, and identify strains of purple nonsulfur bacteria (PNSB), which can fix nitrogen (N), from soil and water in a rice-shrimp integrated system, (ii) to determine the capacity of the selected potent PNSB strains in producing plant growth promoting substances. The isolation resulted in 57 pure PNSB strains from 36 soil samples and 36 water samples of rice-shrimp paddy fields in Thanh Phu - Ben Tre. Among them, 49 strains survived under pH 5.0 conditions, 24 of which grew well under microaerobic light (ML) and aerobic dark (AD) conditions in a basic isolation medium (BIM) containing NaCl 5‰. Two strains (S01 and S06) with the greatest N fixation were identified by 16S rRNA techniques as Rhodobacter sphaeroides. Their N production was 16.9 mg L-1 under the ML condition and 32.1 mg L-1 under the AD condition. Moreover, two R. sphaeroides S01 and S06 strains performed P solubilization at 0.382-2.954 mg L-1 from Al-P, 3.81-4.28 mg L-1 from Fe-P, and 3.87-4.74 mg L-1 from Ca-P, and production of plant growth promoting substances, such as IAA (12.3-15.5 mg L-1), EPS (1.09-1.58 mg L-1), siderophores (10.7-53.6%) and ALA (1.68-2.82 mg L-1) under both the incubating conditions.

Biogas digestive effluent (BDE) is a nutrient-enriched source that can be utilized as an organic fertilizer for rice cultivation without synthetic fertilizer (SF) application. However, a primary concern is the stimulation of methane (CH4) emissions due to the enrichment of the labile organic carbon, a favorite substrate of methanogenic archaea. Methanotrophs potentially reduce greenhouse gas (GHG) emissions from rice fields owing to metabolizing CH4 as a carbon source and energy. We therefore examined the effect of the application of methanotroph-inoculated BDE to the rice cultivated paddy soil on GHG emissions and rice productivity under a pot experiment. Methanotrophs (Methylosinus sp. and Methylocystis sp.), isolated from the Vietnamese Mekong Delta’s rice fields, were separately inoculated to the heated BDE, followed by a 5-day preincubation. Methanotroph-inoculated BDE was supplied to rice cultivation to substitute SF at 50% or 100% in terms of nitrogen amount. The results showed that the total CH4 emissions increased ~34% with the application of BDE. CH4 emissions were significantly reduced by ~17–21% and ~28–44% under the application of methanotroph-inoculated BDE at 100% and 50%, respectively. The reduction in CH4 was commensurate with the augmentation of pmoA transcript copy number under methanotroph-inoculated BDE. In addition, methanotroph-inoculated BDE application did not increase nitrous oxide (N2O) emissions and adversely affect rice growth and grain productivity. This study highlighted the BDE-recirculated feasibility for a lower CH4 emission rice production based on methanotrophs where high CH4-emitting fields were confirmed.

The term “Discourse Awareness” is a new concept in Vietnam. Discourse awareness, conceptualized as a classroom pedagogy, can improve students’ language capacity and has gained popularity over time. Our literature review suggested that there has been little research into this domain locally in Vietnam. This paper aims to discuss the ecology of the concept, examine its developments in Vietnamese tertiary education, and make some arguments for raising students’ discourse awareness in teaching and learning English. It introduces the literature review on discourse awareness in Vietnam, which presents an overview of the supportive role of discourse awareness development in English language teaching and learning. Findings outlined how discourse awareness-raising activities have extensively and successfully been exploited in language classrooms through teaching and learning practices, teacher education, literacy development, and maximizing the cultural competence of language learners. Since then, it is reasonable to hold a strong belief that discourse awareness can serve as an enabling tool to facilitate students’ communication.

The objective of this study was to evaluate the antagonistic activity of Trichoderma spp. against wild pathogen Fusarium oxysporum F.28.1A, which causes wilt disease on sesame. Twenty-six isolates of Trichoderma spp. isolated from soil samples were tested to control F. oxysporum F.28.1A. Prescreening showed that five isolates were T-02B1, T-18B2, T-20B1, T-28B1, and T-29A1, based on the lowest values of colony radius of F. oxysporum F.28.1A. The selected isolates were identified by their ITS region as T. yunnanense T-02B1, T. lentiforme T-18B2, T. asperellum T-20B1, T. hamatum T-28B1, and T. hamatum T-29A1, with similarities around 96–100%. The isolates selected were able to produce enzymes including chitinase, exo-β-1,3-glucanase, and endo-β-1,3-glucanase at levels of 0.34–0.44, 0.017–0.034, and 0.032–0.121 UI · ml –1, respectively, which were considered to be a mechanism to prevent the growth of F. oxysporum F.28.1A. The isolates tested were applied in soil pots to prevent damage from F. oxysporum F.28.1A as a following experiment. The greenhouse experiment was arranged in a completely randomized design with 10 treatments, including a negative control, application of only F. oxysporum F.28.1A, application of both F. oxysporum F.28.1A and fungicide chemicals, application of both F. oxysporum F.28.1A and Trichoderma spp. DHCT, application of T. yunnanense T-02B1, application of T. lentiforme T-18B2, application of T. asperellum T-20B1, application of T. hamatum T-28B1, application of T. hamatum T-29A1 and a mixture of the five selected isolates of Trichoderma spp. with their total population equal to that in individual strain application. The results showed that the five mixed isolates of Trichoderma had a synergistic effect on the reduction of the disease’s prevalence by 35% compared to the negative control treatment.

Teacher questioning is common interaction in classrooms, which seems to be an effective tool to stimulate and enhance teaching and learning. This paper aims to investigate English teachers’ questioning strategies in connection with student learning behavior from a discourse perspective at the University of Foreign Languages, Hue University, Vietnam, within a case study of a Reading class at the English Department. One teacher and 30 students voluntarily participated in the study. Data were collected via audio recordings and classroom observation of 06 teaching hours for Reading classes. Critical Discourse Analysis Theory and Constructivist Learning theories were applied as the analysis and explanation frameworks. Results revealed that teachers employed various discourse strategies for questioning to enhance students learning behavior such as eliciting responses, checking comprehension, and soliciting agreement question functions; which helped arouse students’ interest in the upcoming reading texts, prepare them for vocabulary learning and background knowledge forming, and guide them through the process of reading comprehension skill practice. The paper also addressed implications and suggestions to help teachers exploit teachers’ questioning more effectively in language teaching.

Stem-end rot disease has been causing damage to the production of pomelos in Vietnam. The cur-rent study aimed to (i) isolate fungal pathogens causing pomelo stem-end rot disease (PSERD) and (ii) discover Trichoderma spp. that had an antagonistic ability against pathogens under in vitro conditions. Fungi causing PSERD were isolated from pomelo fruits with symptoms of stem-end rot disease and collected from pomelo farms in Ben Tre province, Vietnam. Moreover, 50 fungal strains of Trichoderma spp. also originated from soils of these pomelo farms in Ben Tre province and were dual-tested with the fungal pathogen on the PDA medium. The results demonstrated that 11 pathogenic fungi causing PSERD were isolated from the fruit and showed mycelial growth of roughly 5.33–8.77 cm diameter at 72 h after inoculation. The two fungi that exhibited the fast-est growth, namely, S-P06 and S-P07, were selected. ITS sequencing of the S-P06 and S-P07 fungi resulted in Lasiodiplodia theobromae. All the 50 Trichoderma spp. strains were allowed to antago-nize against the S-P06 and S-P07 strains under in vitro conditions. The greatest antagonistic effi-ciency was found in Trichoderma spp. T-SP19 at 85.4–86.2% and T-SP32 at 84.7–85.4%. The two antagonists were identified as Trichoderma asperellum T-SP19 and T-SP32. The selected strains of Trichoderma asperellum were potent as a biological control for fruit plants.

The aim of this study was to determine the proper combination of nitrogen (N) fertilizer level and nitrogen fixing endophytic bacteria (NFEB) supplementation for the maximum grain yield of sesame cultivated in alluvial soil in dykes. The experiment followed a completely randomized block design with two factors. The first one was the levels of N fertilizer used, including 0, 50, 75, and 100% N of recommended fertilizer formula (RFF), and the other consisted of no bacteria applied, an individual strain of Enterobacter cloacae ASD-48 or E. cloacae ASD-21 applied, and their mixture, with 5 replicates. The results revealed that fertilizing with 100% N of RFF led to an enhancement of the plant height (16.8 cm), the chlorophyll a and b and their total content (6.45, 1.86, and 8.30 μg mL−1), the number of capsules per plant (7.22 capsules plant−1), the total N uptake (126.5 mg N pot−1), and the grain yield (9.08 g pot−1), in comparison to no N fertilizer applied. Supplementation of two NFRB strains enhanced the soilconcentrations of NH4+ and NO3−, the total N uptake, and the grain yield. The treatment fertilized with 75% N of RFF plus an individual NFEB strain or their bacterial mixture had equivalent total N uptake to that the treatment fertilized with 100% N of RFF had, 120.8–125.5 mg N pot−1 compared to 124.4 mg N pot−1. Regarding the sesame yield, with a reduction by 25–50% N of RFF plus ASD-48 and ASD-21, either individually or in mixture, it increased by 2.39–8.56%, compared to that in the treatment fertilized with 100% N of RFF.

The study was aimed to assess the potency of nitrogen (N)-fixing purple non-sulfur bacteria (NF-PNSB) on ameliorating soil quality, N uptake, and yield of pineapple in acid sulfate soil. The experiment, following a completely randomized block design, had two factors: (i) supplementation of biofertilizers containing the NF-PNSB (No applied bacteria, Rhodobacter sphaeroides W15, W39, and a mixture of both W15 and W39) and (ii) levels of N fertilizer [0, 50, 75, and 100% N of recommended fertilizer formula (RFF)]. Results demonstrated that supplying biofertilizers containing the mixture of both W15 and W39 increased the values of pHH2O and NH4+, and decreased the values of EC, Al3+, and Fe2+ at a soil depth of 0-20 cm, in comparison with the no supplied biofertilizers, by 15.8, 39.9, 26.9, 17.8, and 52.9%, respectively. Applying biofertilizers enhanced the total N uptake by 28.9%, resulting in greater growth and a 22.9% increase in pineapple yield, in comparison with the no biofertilizers supplied treatments. Supplying the two strains W15 and W39 not only contributed to reducing 25% N of RFF but also preserved the pineapple yield, compared to the fertilizing 100% N of RFF. Both W15 and W39 are potent for use as crop yield enhancers. [ABSTRACT FROM AUTHOR]

Basing principally on Fairclough's theory of Critical Discourse Analysis (2001) and Halliday's Systemic Functional Grammar (1994), Feminist Critical Discourse Analysis was initiated in "Feminist Critical Discourse Analysis - Gender, Power and Ideology in Discourse" by Lazar (2005) is developed into a discourse research approach that sheds interest on the relationship between gender power and language or language use. Following this research approach, this paper outlines a detailed study of the grammatical features of journalistic discourse written about women in Vietnamese Women Newspapers, issues of 2021, from the perspectives of Feminist Critical Discourse Analysis, of which the grammatical features of journalistic discourse would be expressed in three aspects: experiential, interpersonal, and expressive values. More specifically, the experiential values of grammar were reflected in the transitivity processes, the interpersonal values were shown in modes of sentences, and finally, the expressive values were realized in the expressive modality. The study results revealed that the three most frequently used processes were material, relational and verbal. Besides, declarative sentence type was used most frequently, and there was very little likelihood of modal word use. These grammatical features were consistent with the news genre applied for newspapers while remaining ample contextual conditions for reflecting journalists' perceptions of women and feminism. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of purple non-sulfur bacteria (PNSB) biofertilizers on soil properties, nitrogen (N) and phosphorus (P) uptakes, growth, and grain yield of sesame cultivated on salt-affected soil. N2-fixing and P-solubilizing bacteria used as biofertilizers were PNSB Rhodopseudomonas palustris VNW64, VNS89, TLS06 and VNS02, and endophytic bacteria (EB) Enterobacter cloacae X4 and Burkholderia acidipaludis X5. The experiment was conducted in a completely randomized block design, with 9 treatments (i) 100% N and 100% P of recommended fertilizer formula (RFF), (ii) 75% N and 50% P, (iii) 50% N and 50% P, (iv) treatment ii plus PNSB biofertilizers, (v) treatment iii plus PNSB biofertilizers, (vi) treatment ii plus EB biofertilizers, (vii) treatment iii plus EB biofertilizers, (viii) PNSB biofertilizers only, and (ix) carriers only, a rice straw and hush ash mixture. Results revealed that application of PNSB biofertilizers significantly improved soil fertility, nutrient uptakes, and yield as compared to treatments that used chemical fertilizers with or without EB biofertilizers at the same amount of N and P fertilizers applied. The use of 75% N and 50% P of RFF plus PNSB biofertilizers enhanced soil pHH2O, NH4+, soluble P, and N, P uptakes in sesame as compared to 100% N and 100% P of RFF. PNSB biofertilizers not only reduced 50% N and 50% P of RFF, but also maintained yield as compared to the treatment using 100% N, P of RFF (6.06 and 6.09 g pot−1, respectively) and limited Na uptake in sesame and Na+ concentration in the soil. [ABSTRACT FROM AUTHOR]

This study aimed to (i) select endophytic bacteria in maize root for its phosphorus solubilization ability and (ii) evaluate the efficacy of selected indigenous bacterial strains on soil fertility, phosphorus (P) uptake, growth, and maize yield. A total of 31 maize root samples were collected from An Phu District, An Giang Province, to isolate the bacteria. In addition, the pot experiment was conducted with nine treatments of (i) 100% P of the recommended fertilizer formula (RFF), (ii) 75% P of the RFF, (iii) 50% P of the RFF, (iv) 25% P of the RFF, (v) 75% P of the RFF plus a mixture of the 3 selected strains, (vi) 50% P of the RFF plus a mixture of the 3 selected strains, (vii) 25% P of the RFF plus a mixture of the 3 selected strains, (viii) 0% P of the RFF plus a mixture of the 3 selected strains, and (ix) 0% P of the RFF plus none of the 3 selected strains. The results identified 72 isolates from LGI medium. All isolates were screened in a broth medium at pH 5.0, but only 16 isolates obtained OD660 > 0.5. All 16 isolates were able to solubilize various insoluble P fractions. Of those, strain ASD-21 had the highest P solubilization ability for the insoluble Al-P compound. Strains ASD-08 and ASD-21 had the highest Fe-P concentration at 39.8-41.5 mg P L-1. Strains ASD-08 and ASD-21 had the highest Ca-P concentration (46.6-51.3 mg P L-1) for 48 h of incubation. They were identified as Enterobacter spp. Results also showed the application of a mixture of strains ASD-08, ASD-10, and ASD-21 increased soil fertility by increasing phosphorus content by 13.7 mg P kg-1 and replacing 25% of P fertilizer, but this mixture did not change maize yield. [ABSTRACT FROM AUTHOR]

Human activities are drastically altering water and material flows in river systems across Asia. These anthropogenic perturbations have rarely been linked to the carbon (C) fluxes of Asian rivers that may account for up to 40-50 % of the global fluxes. The primary object of this review was to provide a conceptual framework for assessing human impacts on Asian river C fluxes, along with a latest update on anthropogenic alterations of riverine C fluxes, focusing on the impacts of water pollution and river impoundments on CO2 outgassing from the rivers draining South, Southeast, and East Asian regions that account for the largest fraction of river discharge and C exports from Asia and Oceania. Recent booms in dam construction across Asia have created a host of environmental problems; yet only a small number of studies have explicitly investigated altered rates of greenhouse gas (GHG) emissions and organic C transport. There have been contrasting reports on impoundment effects: decreases in GHG emissions in the reservoirs exhibiting enhanced primary production vs. increased emissions from the flooded vegetation and soils in the early years following dam construction or from the impounded river reaches and downstream estuaries during the monsoon period. These contrasting results suggest that the rates of metabolic processes in the impounded and downstream reaches can greatly vary longitudinally over time, as a combined result of diel shifts in the balance between autotrophy and heterotrophy, seasonal fluctuations between the dry and monsoon periods, and a long-term change from a leaky post-construction phase to a gradual C sink. Rapid pace of urbanization across southern and eastern Asian regions has dramatically increased municipal water withdrawal, generating annually 120.2 km³ of wastewater in 24 countries, which comprises 38.6 % of the global municipal wastewater production (311.6 km³). Although the municipal wastewater constitutes only 0.9 % of the renewable surface water, it can disproportionately affect the receiving river water, particularly downstream of rapidly expanding metropolitan areas, including eutrophication, increases in the amount and lability of organic C, and pulse emissions of CO2 and other greenhouse gases (GHGs). As reviewed for three representative rivers (the Ganges, Mekong, and Yellow River), the lower reaches of these rivers and their polluted tributaries tend to exhibit higher levels of organic C and the partial pressure of CO2 (pCO2) than the eutrophic reservoirs and less impacted upstream reaches. More field measurements of pCO2, together with accurate flux calculations based on river-specific model parameters, are urgently required to provide more accurate estimates of GHG emissions from the Asian rivers that are now underrepresented in the global C budgets. Researchers working on individual river systems need to be linked to collaborative research networks to facilitate global synthesis of local field data. These synthesis efforts, combined with conceptual and mathematical models, will contribute to a better understanding of how anthropogenic perturbations in rapidly urbanizing watersheds across Asia and other continents enhance discontinuities in riverine metabolic processes and C fluxes and hence transform the natural river assumed in the long-standing river continuum model to an anthropogenic system. [ABSTRACT FROM AUTHOR]

Large construction projects are inherently complex and dynamic. A comprehensive answer on how to manage such projects successfully is difficult to provide. This paper expounds on the success factors for large construction projects in Vietnam. A survey questionnaire was used to collect data from practitioners. Factor analysis was employed to categorize these success factors perceived by 109 respondents from 42 construction-related organizations. Factor analysis uncovered that these success factors can be grouped under tour categories. here titled the four COMs: comfort, competence, commitment, and communication. The result can be used as a guideline to successfully handle construction projects in Vietnam as well as in other countries, especially in the emerging economies in Asia and the rest of the world. [ABSTRACT FROM AUTHOR]