THE EFFECT OF USING INSTRUCTIONAL RUBRICS ON EFL STUDENTS’ WRITING PERFORMANCE: A HIGH SCHOOL CASE IN THE MEKONG DELTA OF VIETNAM

Teaching EFL writing has been one of the most trending research fields recently. Among the techniques being tested, using instructional rubrics has drawn much attention from researchers and teachers. This study aimed to investigate the effectiveness of using rubrics in enhancing students’ writing skill and the students’ attitudes towards this technique. The study used the experimental research design. The participants were thirty English-majored eleventh-grade students (N=30) in a high school in Can Tho City, Viet Nam. The main research tools included two guiding rubrics, one writing pre-test, two writing post-tests, and a questionnaire. Holistic and analytic rubrics were used in the teaching of writing skill to the participants to help them understand the targets for learning and the standards of quality for their writing work.  Data from the pre- and post- writing tests indicated significant changes in students’ writing performance after using both holistic and analytic rubrics. Besides, the results of the questionnaire revealed learners’ positive perceptions of this technique. It could be suggested that high school teachers should take into account the use of rubrics in teaching writing for EFL students.  Article visualizations

Impacts of fallow conditions, compost and silicate fertilizer on soil nematode community in salt–affected paddy rice fields in acid sulfate and alluvial soils in the Mekong Delta, Vietnam

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)Avoidance of intensive rice cultivation (IRC) and soil amendments are potential practices to enhance soil properties. There is only limited information on the effects of reduced IRC and its mixture with compost or silicate fertilizer (Si) on the soil nematode community in salt–affected soils. This study aimed to assess the shifts of soil nematode community by reducing a rice crop from triple rice system (RRR) to a double rice system and mixed with compost or Si in paddy fields in acid sulfate soil (ASS) and alluvial soil (AL) in the Mekong Delta, Vietnam. Field experiments were designed with four treatments in four replicates, including RRR and a proposed system of double–rice followed by a fallow (FRR) and with 3 Mg ha–1 crop−1 compost or 100 kg ha–1 crop−1 Si. Soils were collected at harvest after the 2 year experiment, reflecting the fifth and third consecutive rice crop in RRR and FRR system, respectively. Results showed that reduced IRC gave a significant reduction in abundance of plant–parasitic nematodes (PPN), dominated by Hirschmanniella and increased abundance bacterivorous nematodes when mixed to compost and silicate fertilizer in ASS. In addition, reduced IRC increased nematode biodiversity Hill’s indices and reduced herbivorous footprint in ASS. Proposed system having compost or Si had strongly increased in bacterivorous and omnivorous footprints. Particularly, reduced IRC mixture with Si increased abundance of Rhabdolaimus, Mesodorylaimus and Aquatides, metabolic footprints (structure footprint, bacterivorous, omnivorous and predator) and diversity Hill’s N1 index in ASS. Our results highlighted that reduced IRC was a beneficial practice for decreasing abundance of PPN in salt-affected soils and increasing abundance of FLN in ASS. IRC mixture with compost or Si had potential in structuring the nematode communities with increasing biodiversity, trophic structure, and metabolic footprintsPeer reviewedFinal Accepted Versio

Potential Use of Rice Husk Biochar and Compost to Improve P Availability and Reduce GHG Emissions in Acid Sulfate Soil

© 2020 by the authors. Acid sulfate soil (ASS) has major problems related to phosphorus deficiency and high potential for N2O emissions, as well as strong acidity. The objective of this study was to evaluate the effects of rice husk biochar and compost on P availability and greenhouse gas (GHG) emissions in ASS in in vitro incubation studies. An ASS was amended with two types of rice husk biochar (at rates of 0 g kg-1, 20 g kg-1, and 50 g kg-1, equivalent to 0 Mg ha-1, 20 Mg ha-1, and 50 Mg ha-1, assuming that bulk density was 1 g cm-3 and evenly applied for 10 cm in depth) and compost (at rates of 0 g kg-1, 10 g kg-1, and 20 g kg-1, equivalent to 0 Mg ha-1, 10 Mg ha-1, and 20 Mg ha-1) and incubated. Application of compost increased labile P by 100% and 200% at rates of 10 g kg-1 and 20 g kg-1, respectively. Both biochars showed an increase in NaHCO3-soluble inorganic P by 16% to 30%, decreases in NaOH-soluble inorganic P and NaHCO3-soluble organic P. N2O emissions were significantly decreased by 80% by a biochar with a higher surface area and higher NH4+ adsorption capacity at a rate of 50 g kg-1 as compared with those in un-amended soil. In contrast, compost amendment at a rate of 10 g kg-1 significantly increased N2O emission by 150%. These results suggest that in ASS, whilst compost is more effective in improving P availability, biochar is more effective in mitigating GHG emissions, emphasizing that fundamental characteristics of organic amendments influenced the outcomes in terms of desirable effects

Inland dry season saline intrusion in the Vietnamese Mekong River Delta is driving the identification and implementation of alternative crops to rice

CONTEXT: Inland saline intrusion is occurring during the dry season in the Mekong River Delta (MRD), Vietnam. Rising sea levels, tidal fluctuations, drought, and changes to upstream flow contribute to extensive salinisation of rice producing areas of the MRD, leading to substantial rice crop losses. OBJECTIVE: The identification, evaluation and implementation of alternative crop and soil management solutions are required to complement on-going rice production in the region. METHODS: A review of scientific and grey literature was conducted regarding the nature and extent of salinisation in the MRD and the adoption and management of alternative crops to rice. RESULTS: Familiar crops in Vietnam (e.g., maize, soybean), as well as novel crops to the MRD (e.g., quinoa, cowpea) were explored as potential options to replace dry season rice. Management options including surface soil mulches and plastic coverings help maintain soil moisture and reduce salinity damage to plants, and the use of drainage and seed preparation techniques can improve plant establishment and yield. Factors contributing to the success of alternative crops include salt tolerance, timing and efficiency of water use, ability to grow in the dry growing season, tolerance to pests and diseases, labour intensiveness and the crops' marketability. SIGNIFICANCE: The identification of suitable alternative crops to replace dry season rice in saline affected areas of the MRD, combined with management practices like mulching and soil moisture monitoring, could provide farmers with income opportunities to offset rice losses. Documenting the factors contributing to successful crop diversification can assist with decision-making and support initiatives among farmers, agribusiness, and government agencies

TextANIMAR: Text-based 3D Animal Fine-Grained Retrieval

3D object retrieval is an important yet challenging task, which has drawn more and more attention in recent years. While existing approaches have made strides in addressing this issue, they are often limited to restricted settings such as image and sketch queries, which are often unfriendly interactions for common users. In order to overcome these limitations, this paper presents a novel SHREC challenge track focusing on text-based fine-grained retrieval of 3D animal models. Unlike previous SHREC challenge tracks, the proposed task is considerably more challenging, requiring participants to develop innovative approaches to tackle the problem of text-based retrieval. Despite the increased difficulty, we believe that this task has the potential to drive useful applications in practice and facilitate more intuitive interactions with 3D objects. Five groups participated in our competition, submitting a total of 114 runs. While the results obtained in our competition are satisfactory, we note that the challenges presented by this task are far from being fully solved. As such, we provide insights into potential areas for future research and improvements. We believe that we can help push the boundaries of 3D object retrieval and facilitate more user-friendly interactions via vision-language technologies.Comment: arXiv admin note: text overlap with arXiv:2304.0573

Colorimetric analysis is not sufficient to estimate bioavailable phosphorus in a hypersaline aquatic environment

Colorimetric analysis is commonly used to quantify P availability in aquatic environments. However, it may not be adequate to quantify the bioavailability of dissolved organic P compounds. This study aimed to investigate to what extent the colorimetrically measurable P fractions can be utilized by algae, with a particular emphasis on organic P compounds in a hypersaline aquatic environment. In this study, the growth of the marine alga Dunaliella tertiolecta Butcher was observed in axenic hypersaline cultures prepared with different organic P forms and related to the corresponding levels of colorimetrically measured P and total P. The malachite green method was used to colorimetrically analyze the different P forms and inductively coupled plasma-optical emission spectroscopy was used to quantify the total P. The results showed that only creatine P was colorimetrically detectable, of which 87% of its total concentration was measured. The growth of algae in the culture media with organic P compounds did not reflect the colorimetrically measurable organic P compounds. The results from this study imply that colorimetric analysis may not be sufficient to assess P availability to algae in hypersaline conditions where organic P components are the main source of P

Land use change from permanent rice to alternating rice-shrimp or permanent shrimp in the coastal Mekong Delta, Vietnam: Changes in the nutrient status and binding forms

Saline water intrusion has become a severe threat in the coastal areas of Mekong delta of Vietnam, though offering farmers the option to diversify their land use, and switching, for instance, from permanent rice to alternating rice-shrimp systems or even to permanent shrimp systems. The objective of this study was to evaluate the respective impacts on soil salinity, nutrient status and their binding forms. Hence, we sampled the topsoils (cultivation layer, 0–15 cm) from 10 permanent rice systems and the rice platforms of 10 alternating riceshrimp systems. Furthermore, the sludges and the soils 10 cm underneath of the sludges from the ditches of the alternating rice-shrimp as well as from ponds of the permanent shrimp systems were sampled in Bến Tre and Sóc Trăng provinces, Vietnam, respectively. The samples were analyzed regarding their electric conductivity, total and plant-available nutrient contents. To reveal possible changes in nutrient binding forms, sequential P and S extraction, 31P-nuclear magnetic resonance spectroscopy, and S and P X-ray absorption near edge structure spectroscopy were applied. The results showed that permanent and alternating shrimp cultivation lead to elevated salt concentrations but also improved the overall nutrient status relative to the permanent rice management and especially in the sludges relative to the soils underneath. The continued deposition of shrimp and feed debris promoted the accrual of stable, Ca- and Mg-associated P forms as well as of P-monoesters, whereas the S forms were depleted in thiophene S groups but enriched in sulfides relative to permanent rice fields. As effects by alternating rice-shrimp management were intermediate, this management has more potential to serve as a no-regret strategy for farmers to remain flexible in their response to climate changes and concurrent salinity intrusion relative to permanent shrimp production, which requires strict maintenance of adequate salinity levels also during the rainy season

Growth of Chaetoceros calcitrans in sediment extracts from Artemia franciscana culture ponds points to phosphorus limitation

Chaetoceros calcitrans is one of the most suitable algal strains to feed Artemia because of its appropriate size, digestibility, absence of toxins, and nutritional value. Apart from light and temperature, the growth of C. calcitrans in Artemia ponds in the Mekong Delta of Vietnam depends on the supply of nutrients, especially nitrogen (N) and phosphorus (P) released from the pond bottom sediments. This study was carried out to investigate the growth of C. calcitrans in relation to the availability and proportions of N and P present in the extracts of Artemia pond bottom sediments. The results show that the sediments are depleted in dissolved reactive P (DRP) and highly unbalanced in terms of the ratio of dissolved inorganic N (DIN) to DRP. Algal density and biomass were significantly higher in the extracts with DRP concentrations above 0.1 mg P/L and DIN/DRP ratios below 100