Some Obstacles In Mathematical Communication Of Students While Learning Continous Functions Lesson

Mathematical Communication is one of the required competencies of the learner in the needs of the real life, and in learning Mathematics, students always have the need to communicate with teacher and other students to solve problems in mathematics, as well as to present the solution or mathematical ideas to the others. However, there are many difficulties with many reasons when they exchange or communicate with the others by mathematical language in classroom. Therefore, the ability for communicating in Math is one of the required competencies of students. In this paper, we try to find out the obstacles which make students have difficulty when they are in mathematical communication while learning continuous functions. The problems set out in this article to assess how difficulties in communication in the Math class, so that we can recommend some possible strategies for teachers to help their students in order to overcome these obstacles in practicing teaching

The Impact of Job Satisfaction on Job Performance of Tax Officials: An Empirical Study in Vietnam

Purpose: The level of employee satisfaction with the use of e-tax systems is a major factor influencing the success of such systems. While studies typically focus on taxpayers' perspectives, this research investigates the influence of perceived ease of use, IT background, incentives, and social influence on tax officials’ job performance, mediated by tax officials’ job satisfaction.   Theoretical framework: The research is based on the Theory of Planned Behavior (TPB) and Technology Acceptance Model (TAM) to propose the research model which analyze the impact of job satisfaction on job performance.    Design/Methodology/Approach: A quantitative approach was adopted, involving surveys administered to tax officials in Vietnam. The study analyzed 250 valid responses using Cronbach's test, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Structural Equation Modeling (SEM).   Findings: The research revealed that all four factors significantly influence job performance through job satisfaction of tax officials in Vietnam. These findings provide valuable insights for tax authorities to improve job performance.   Research, Practical & Social implications: The research results contribute to other countries with similar characteristics in devising strategies to enhance employee performance. However, its limitations include its generalizability to other e-tax systems and countries. Future research with a larger sample size could bolster the applicability of these findings nationally.   Originality/Value: The research suggests tax authorities to support tax officials improve their professional skills; improve the regulations, policies on salary and bonus for tax officials; assist tax officials in using the e-tax system; implement effective communication

Factors Affecting Successful Quality Assurance Implementation in Vietnamese Higher Education: A Qualitative Study

Quality assurance and accreditation was officially introduced into the higher education system in Vietnam over ten years ago. It is evident that quality assurance has resulted in positive impacts on university management, teaching, learning and research activities. This paper aims to explore factors that aid the successful implementation of higher education quality assurance and accreditation in Vietnam. Through semi-structured interviews with 32 participants, this study identified a number of factors that contributed to quality assurance processes, including awareness of the importance of quality assurance, better institutional manager leadership, support of university lecturers, staff, and students, and the vital responsibility of internal quality assurance staff. These confirm that internal stakeholders play an important role in undertaking quality assurance programmes and activities

A Bibliometric Review on Realistic Mathematics Education in Scopus Database Between 1972-2019

Despite receiving increasing attention from mathematics education scholars, there has not yet been any overall understanding of the current state of realistic mathematics education (RME). To address this gap, this study aims to provide a review of 288 studies on realistic mathematics education from the Scopus database between 1972 and 2019. Using descriptive and bibliometric analyses, this study addresses four research issues as follows: (i) the total volume, growth trajectory, and geographic distribution; (ii) the most influencing authors and research groups; (iii) the most influencing sources (i.e., journals, books, conferences); and (iv) the most important topics. Several implications for not only mathematics education scholars but also other stakeholders, including policymakers, school managers, mathematics teachers, may not be considered in this study

Effects of different plant growth regulators as the foliar application on growth and flower quality of potted rose (Rosa chinensis Jacq. cv. Nhung)

This study was conducted to evaluate the different concentrations of Naphthalene acetic acid (NAA), Benzyladenine (BA) and Gibberellic acid (GA3­) as foliar applications on growth and flower quality of potted rose Nhung (Rosa chinensis Jacq. cv. Nhung). The experiment was constructed in a completely randomized design, that included seven treatments, such as control (sprayed water), NAA, BA and GA3 at two different concentrations of 25 and 50 ppm, in six replications, with one plant/pot for each replication. The chemical solutions were applied three times at an interval of fifteen days. The results revealed that some plant growth regulators increased the growth and flowering time of rose cv. Nhung. Using pre-harvest foliar sprays of NAA and BA at 25 and 50 ppm concentrations showed maximum bud diameter, flower diameter and flowering duration as compared with the control treatment. The concentration of  GA3 foliar application at 25 ppm increased plant growth (the height of flowering branches and Spad values) without affecting flower quality values and the flowering duration in comparison with the control treatment

Isolation an agar degradation Bacillus sp. AT6 and preliminary application for seaweed saccharification

Background: Agar is a common polysaccharide found in nature. However, agar is strongly resisted to the degradation processing, leading to limitation of its application in various areas. Thus, finding an effective solution for agar saccharification significantly improves the economically effects of agar based substrates.Methods: Soil samples were collected from TienPhong Forestry Ltd. Company, ThuyXuan District, ThuaThien Hue province, Vietnam. Potential agar degrading bacteria were screened on a mineral salt agar medium. The isolate was identified based on 16S rRNA nucleotide sequence, morphological, physiological, and biochemical characteristics. Agarase production was evaluated by modification culture conditions including incubation time, shaking speed, and initial inoculum size. Molecular mass of extracellular agarase was determined by native SDS-PAGE. The effect of pH, temperature, metal ions, and organic solvents were conducted for enzyme characterization. Application of enzyme was investigated on seaweed saccharification.Result: An agar degrading bacterial strain was isolated from soils and identified as Bacillus sp. AT6. Maximal agarase accumulation obtained in the culture containing an inoculum size of 10% (v/v), shaking speed of 210 rpm, and 96 hours incubation. The agarase revealed a single band on zymogram analysis with an apparent molecular weight of 180 kDa. The optimal temperature and pH were 40°C and pH 8.0, respectively. All tested metal ions and organic solvents partially decreased enzyme activity. Treatment seaweed by agarase resulted in reducing sugars release present in the reaction, indicating the saccharification of seaweed was succeeded.Conclusion: Bacillus sp. AT6 is a new report of agarolytic bacteria that produces extracellular agarase enzymes. The present results promise strain AT6 is a great candidate for agar saccharification for industrial application

ĐẶC ĐIỂM PROTEASE NGOẠI BÀO TỪ CHỦNG Bacillus tequilensis ON1

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

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

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

Screening yeast strains for alcohol fermentation from the dried traditional yeast

Methods to produce rice alcohol by dried traditional yeast are unstable because the yeast system in dried traditional yeast has depended on nature and not been controlled. In this study, a total of 15 different kinds of dried traditional yeast were prepared and screened. Each yeast strain was evaluated by analyzing its fermentation property and alcohol tolerance. There are 19 yeast strains were isolated and their growth conditions and ethanol producing properties were examined. Results showed that three strains S1, BT, BL3 grew and produced ethanol at temperature 28-30oC, and pH 5-5.5. Especially, high concentration ethanol tolerance ability of the three strains was at 8-18%. Our results showed that these strains were valuable microorganisms and could be utilized as a basis for further study of dried traditional yeast in traditional alcoholic beverages

Simultaneously induced mutations in eIF4E genes by CRISPR/Cas9 enhance PVY resistance in tobacco

Tobacco is an important commercial crop and a rich source of alkaloids for pharmaceutical and agricultural applications. However, its yield can be reduced by up to 70% due to virus infections, especially by a potyvirus Potato virus Y (PVY). The replication of PVY relies on host factors, and eukaryotic translation initiation factor 4Es (eIF4Es) have already been identified as recessive resistance genes against potyviruses in many plant species. To investigate the molecular basis of PVY resistance in the widely cultivated allotetraploid tobacco variety K326, we developed a dual guide RNA CRISPR/Cas9 system for combinatorial gene editing of two clades, eIF4E1 (eIF4E1-S and eIF4E1-T) and eIF4E2 (eIF4E2-S and eIF4E2-T) in the eIF4E gene family comprising six members in tobacco. We screened for CRISPR/Cas9-induced mutations by heteroduplex analysis and Sanger sequencing, and monitored PVY(O) accumulation in virus challenged regenerated plants by DAS-ELISA both in T0 and T1 generations. We found that all T0 lines carrying targeted mutations in the eIF4E1-S gene displayed enhanced resistance to PVY(O) confirming previous reports. More importantly, our combinatorial approach revealed that eIF4E1-S is necessary but not sufficient for complete PVY resistance. Only the quadruple mutants harboring loss-of-function mutations in eIF4E1-S, eIF4E1-T, eIF4E2-S and eIF4E2-T showed heritable high-level resistance to PVY(O) in tobacco. Our work highlights the importance of understanding host factor redundancy in virus replication and provides a roadmap to generate virus resistance by combinatorial CRISPR/Cas9-mediated editing in non-model crop plants with complex genomes