Potential to mitigate ammonia emission from slurry by increasing dietary fermentable fiber through inclusion of tropical byproducts in practical diets for growing pigs

Objective: Research was conducted to test the effect of including fiber-rich feedstuffs in practical pig diets on nutrient digestibility, nitrogen balance and ammonia emissions from slurry. Methods: Three Vietnamese fiber sources were screened, namely cassava leaf meal (CL), cassava root residue (CR), and tofu by-product (TF). Accordingly, a control diet (Con) with 10% of dietary non-starch polysaccharides (NSP) and three test diets including one of the three fiber-rich feedstuffs to reach 15% of NSP were formulated. All formulated diets had the same level of crude protein (CP), in vitro ileal protein digestible and metabolisable energy, whereas the in vitro hindgut volatile fatty acid (VFA) production of the test diets was 12% to 20% higher than the control diet. Forty growing barrows with initial body weight at 28.6 +/- 1.93 kg (mean +/- standard deviation) were allocated to the four treatments. When pigs reached about 50 kg of body weight, four pigs from each treatment were used for a nitrogen balance trial and ammonia emission assessment, the remaining six pigs continued the second period of the feeding trial. Results: The TF treatment increased fecal VFA by 33% as compared with the control treatment (p = 0.07), suggesting stimulation of the hindgut fermentation. However, urinary N was not significantly reduced or shifted to fecal N, nor was slurry pH decreased. Accordingly, ammonia emissions were not mitigated. CR and CL treatments failed to enhance in vivo hindgut fermentation, as assessed by fecal VFA and purine bases. On the contrary, the reduction of CP digestibility in the CL treatment enhanced ammonia emissions from slurry. Conclusion: Dietary inclusion of cassava and tofu byproducts through an increase of dietary NSP from 10% to 15% might stimulate fecal VFA excretion but this does not guarantee a reduction in ammonia emissions from slurry, while its interaction with protein digestibility even might enhance enhanced ammonia emission

Analysis of Electromagnetic Parameters of Hybrid Externally Excited Synchronous Motors for Electric Vehicle Applications

This paper presents two different approaches to improve the electromagnetic torque and output power of the hybrid Externally Excited Synchronous Motor (EESM) applied to Electric Vehicles (EVs). An analytical approach is first considered to define the main parameters of the proposed machine. Based on the obtained results from the analytical model, the hybrid EESM is designed with different rotor shapes and step-skewing magnet segments to reduce the total losses and improve torque ripple. Then, Finite Element Analysis (FEA) is applied to compute and simulate electromagnetic parameters, such as the magnetic flux density, mean torque, and output power. The development of these two approaches is validated on an actual EESM machine and the agreement with the theory is shown

Determinants Influencing Entrepreneurial Intention in Hanoi, Vietnam

This research employed survey data from 204 students between two groups of  economics and technical majors in Hanoi city for assessing the impact levels of determinants on entrepreneurial intention. The results show that a number of determinants including Need for achievement, Self-efficacy, and Instrumental readiness have positive impacts on student’s entrepreneurial intention. Besides, this study is also to create a basis for  comparative students among different economics and technical majors, work exoperience, and gender. These findings are the basis to recommend policies and solutions to promote entrepreneurship movement in Vietnam. Keywords: Entrepreneurial intention, need for achievement, self-efficacy, instrumental readiness. DOI: 10.7176/EJBM/12-15-10 Publication date:May 31st 2020

Delay factors in the construction of irrigation and hydropower projects in Vietnam

Irrigation and hydropower are among the most important sectors in the construction industry that propel the economic needs of a developing country like Vietnam. The construction of these projects often suffers from severe delays, leading to financial losses and other negative impacts on the economy. This paper aims to determine delay factors in the construction of these projects. Among many, 39 most important candidates of delay causes were identified from the literature review. Further surveys on project participants were conducted for the severity of these causes. An exploratory factor analysis was utilized to identify latent factors that cause delays in construction projects. The analysis result categorized a few groups of factors such as abnormal factors on the construction site (e.g., labor accidents, hydrology, water flow, extreme weather) and technical factors related to the construction contractor (e.g., unsuitable schedule, outdated construction technology, unprofessional workers) that have the greatest impact on the delay in construction of irrigation and hydropower projects in Vietnam. These findings contribute to the body of knowledge of project management and risk management, hence an improvement in the efficiency of the project sectors’ performance

Electrochemical DNA sensor for label-free soybean transgenic detection

This paper describes the development of electrochemical label- free DNA sensor for detection of transgenic in Round–up Ready Soybean (herbicide tolerance). Two pairs of electrodes which the optimized dimension is 70µm x 30µm (the width of electrode x inter-distance between fingers), were fabricated on a chip for differential measures. The DNA probe (35S 5’-GCT CCT ACA AAT GCC ATC A-3) was designed in such a way that it can hybridize with the CaMV 35S promoter of Roundup Ready soybean. The DNA was immobilized on the surface of the sensor by the mean of (3-aminopropyl)triethoxysilane (APTS) polymer. The response time of DNA sensor is less than 1 second; in case of 100% matching level, the sensitivity is 2 mV/µM. The activity of DNA sensor remains unchanged after 9 months of storage at -4oC in DI water. Some random soybean samples were collected, extracted and tested by the DNA sensor and the results were well matched with the of PCR method

Two decades of studies on learning management system in higher education: A bibliometric analysis with Scopus database 2000-2020

Over the past twenty years, using learning management systems in higher education has attracted increasing interest from researchers around the globe. In this context, the current study aimed to explore the volume, growth trajectory, and geographic distribution of learning management systems in higher education literature, along with identifying impactful authors, sources, and publications, and highlight emerging research issues. The authors conducted bibliometric analysis on 1334 documents, related to the use of learning management systems in the context of higher education, extracted from Scopus database. The findings show a rapidly growing knowledge base on learning management systems in higher education, especially intensely in the years 2015-2020 and primarily from research in developed societies. This flourishing is consistent with the development trend of international education and the strong development of technology. In addition, the core literature was identified based on the volume of publications and citations. The results also reveal the emerging intellectual structure of the field and provide points of reference for scholars studying the discipline. This paper offers a knowledge map for future research assessments of learning management systems in higher education

Mechanism to Detect Pesticide Residues in Tealeaves Based on CdZnSe/ZnS Ternary Alloy Quantum Dots

In this report, we present the optical properties of the biosensors fabricated from CdZnSe/ZnS quantum dots. The optical properties such as absorption and emission of the ternary quantum dots before and after coupling with the protein molecules like streptavidine (SA) and acetylcholinesterase enzymes (AChE), to form a biosensor structure, will be presented. In particular, the changes in luminescence intensity according to the pH value of the solution environment containing biosensor have been considered, before and after the presence of pesticides. The changes in luminescence intensity of the biosensor after the presence of pesticide over time from 2 seconds to 26 minutes were also surveyed. We have been carried out the tests to determine the trace amounts of commercial pesticides like Motox 5EC, containing 5% cypermethrin and Tungatin 10 EC, containing 10% abamectin, on the real samples of tealeaves. Some characteristics of the relationship between composition, structure, and special optical properties of ternary alloy quantum dots will also be presented. These studies open up the potential applications of  ternary quantum dots for agricultural production

DETERMINATION THE PRIORITY OF FACTORS INFLUENCING OVERSEAS INVESTMENT DESTINATIONS OF BUSINESSES USING AN ANALYTIC HIERARCHY PROCESS METHOD

Because of the great benefits overseas investment brings, countries and businesses are increasingly concerned with the question of an ideal investment destination. Many studies have shown that, factors of the consumption market, the infrastructure and resources, economic and political environment have a significant impact on the decision to choose an investment location, however the priority order of these factors are different for various research spaces. By studying the specific case of Viettel Group - one of the largest telecommunications groups in Vietnam that is having many international investment activities in recent years, the study has been verified the priority order of factors influencing the decision to choose an overseas investment location of this corporation. The research outcomes show that the group of factors that have the most influence on investment decisions is the group "Consumption market", more specifically, the sub-factor "Market Size" is considered more than the others.    Keywords: Investment Destinations, Foreign Investment Decision, Analytic Hierarchy Process

Integrated Effect of the Payment for Forest Environmental Services (PFES) in Vietnam

Payment for forest environmental services (PFES) has become an effective management tool for forest resources in the world, especially in developing countries such as Vietnam. The Vietnamese PFES policy has been institutionalized and implemented since 2010, contributing to forest protection and improving the livelihoods of people who depend on forests. In this chapter, the PFES policy was analyzed, followed by the evaluation of the effectiveness of a PFES program applied in the Ba Be district, Bac Kan province, Vietnam in three aspects: environment, economy, and society. Finally, we synthesize the combined effectiveness of the PFES program in Vietnam and offer solutions to improve and promote the PFES policy in Vietnam and developing countries around the world