Validation of the factor structure of the motivated strategies for learning questionnaire

In recent years, the motivated strategies for learning questionnaire (MSLQ) has been used to assess students’ motivational orientations and utilization of various learning strategies. Due to its significant effects on student outcomes such as academic performance and careers, research on the factor structure of motivated strategies for learning has received increasing attention. However, the existing literature indicates a dearth of studies focusing on the MSLQ dimensions in Vietnam. Therefore, this study aimed to ascertain the factor structure of the 31-item Student Motivation Scale (SMS), which is a subset of the larger 81-item MSLQ, in the context of Vietnam. The study utilized the Vietnamese version of the SMS to collect data from 317 high school students in Vietnam. The factorial analysis showed that the SMS has its original six-factor structure, which is made up of task value (TV), control beliefs, self-efficacy for learning and performance (SLP), test anxiety (TA), and intrinsic goal orientation (IGO). The present study recommended that school leaders and teachers should use the SMS to assess students’ motivation in the context of Vietnamese education

THE ASYMMETRIC EFFECTS OF EXCHANGE RATE VOLATILITY ON INTERNATIONAL TRADE IN A TRANSITION ECONOMY: THE CASE OF VIETNAM

This study examines the asymmetric effects of Exchange Rate Volatility (ERV) on Vietnam’s international trade. Using time-series data fitted to the Nonlinear Autoregressive Distributed Lag (NARDL) model, we find that positive changes in ERV have a negative impact on the trade balance in the short-run. On the other hand,increases in ERV have a positive impact on the trade balance in the long-run. We also find that negative changes in ERV do not have any significant effect on the trade balance

Effects of principals’ leadership styles on teachers’ commitment in Vietnam

In recent years, styles of transformational and transactional leadership have become an important area of research because of its significant impact on teachers’ outcomes such as commitment, job satisfaction, self-efficacy. However, the relationships between transformational and transactional leadership styles of school principals and teachers’ organizational commitment have been rarely investigated in the educational context in Vietnam. This study aimed to determine how transformational and transactional leadership styles influence the organizational commitment of Vietnamese high school teachers. The study employed two standardized surveys to collect data from 387 teachers at 24 public high schools in the Mekong Delta of Vietnam. The results of correlation coefficient analyses indicated that teachers’ organizational commitment was positively influenced by transformational leadership and negatively influenced by transactional leadership. In addition, the results of multiple regression analyses showed that the organizational commitment of teachers was predicted by all components of both leadership styles of principals. The present study suggested that school leaders might combine both transformational and transactional leadership styles in their leadership practices to improve teachers’ organizational commitment

Physical Properties and Spray Characteristics of Ultrasound-assisted Emulsion based on Ultra Low Sulphur Diesel and Biodiesel

Using fuels with a no-sulphur or limited-sulphur content for diesel engines has been considered an urgent issue in the reduction of pollution due to the difficulty of controlling sulphur emissions. In this experimental study, ultra-low sulphur diesel (ULSD) originating from fossil fuel and biodiesel from waste cooking oil (WOB) were mixed with ultrasonic assistance. The optimal mixing rate of ULSD and WOB, and the optimal distance of the ultrasound horn tip, were found as 65%:35% and 80 mm, respectively. After 15 minutes of ultrasonic treatment, a ULSD-WOB emulsion was formed, with the highest stability at around 99%, and its physical properties attained constant values. In addition, the spray characteristics of the ULSD-WOB emulsion, the WOB and the ULSD, including the spray penetration and cone angle, were examined and compared to those of fossil diesel fuel (DF). As a result, the ULSD-WOB emulsion produced with the assistance of ultrasound met the strict requirements of fuels used for diesel engines

Development of PSO for tracking Maximum Power Point of Photovoltaic Systems

For a photovoltaic system, the relationship of the output voltage and power is usually non-linear, so it is essential to equip a MPPT controller in PV systems. Furthermore, the hotspot problem is a common phenomenon, resulting from the PV system operating under PSC. Partial shading not only damages the PV cells, but also makes it difficult to find the global MPP in the characteristic curves of P-V. The paper proposes a novel version of PSO, namely PPSO in order to detect the global peak among the multiple peaks, known as the true maximum energy from PV panel. For this, the PPSO algorithm makes the velocity of each particle be perturbed once the particles are struck into a local minima state in order to find the best optimum solution in the MPPT problem. The perturbation in the velocity vector of each particle not only helps them tracking the MPP accurately under the changing environmental conditions, such as large fluctuations of insolation and temperature like PSC; but also removes the steady-state oscillation. The proposed approach has been tested on a MPPT system, which controls a dc-dc boost converter connected in series with a resistive load. Moreover, the obtained results are compared to those obtained without any MPPT controller to prove the efficiency of the suggested method. In addition, this novel version gives the highest accuracy of tracking the optimum power in the least iteration number as compared to the conventional PSO

ENCAPSULATION OF LACTOBACILLUS ACIDOPHILUS IN YEAST CELL WALLS (SACCHAROMYCES CEREVISIAE) FOR IMPROVING SURVIVAL IN GASTROINTESTINAL CONDITIONS

In search of high-quality health products, it is required that probiotic preparations consumed in gastro-intestinal condition remain metabolically active and preserve their activity. Several recent studies, consequently, have focused on probiotic protection via encapsulation in order to optimize probiotics’ viability as well as their delivery into gastro-intestinal environment. The objectives of this study were to find out a new material for encapsulation of probiotics, utilizing capsules prepared from Saccharomyces cerevisiae to protect living probiotic cells. The encapsulation of cells was achieved, using the crack scars of the yeast cell walls (YCW) created by the sonication method. Besides, some probiotic cells can be considered as being encapsulated by some surrounded yeast cells by direct cell-cell contact. It is concluded that thanks to encapsulation by yeast cells, probiotic’s metabolic activity and survival are markedly improved. This suggests a high potential in protecting probiotics from the extreme condition of digestion process and can be applied in protecting probiotic preparations in food formulations as well. It was found that encapsulation yield in this study reached its highest point at 82.008 ± 1.123%. Viability of encapsulated probiotic in simulated gastric juice (SGJ) after 150 minutes is 19.048 ± 2.701%, compared to that of free cells at 0%. Likewise, after a 4-hour treatment in simulated intestinal juice (SIJ) (0.5% bile salt) encapsulated probiotic proves better survival at 56.338 ± 5.094% than free cell at 43.677 ± 2.058%

Review of two genera of freshwater crabs, Larnaudia Bott, 1966 and Neolarnaudia Türkay & Naiyanetr, 1987 (Crustacea: Decapoda: Potamidae) with redescription Neolarnaudiaphymatodes (Kemp, 1923) from Southern Vietnam

ABSTRACT: The occurrence of Larnaudia Bott, 1966 in southern Vietnam remains obscure. Although some previous studies described the presence of Larnaudialarnaudii A. Milne-Edwards, 1869 in Vietnam, our analysis of freshwater crab specimens collected at many locations in southern Vietnam revealed that Neolarnaudia Türkay Naiyanetr, 1987, but not Larnaudia Bott, 1966, is present in southern Vietnam. In this study, we recorded two species of Neolarnaudia, N. phymatodes (Kemp, 1923) and N. botti Türkay Naiyanetr, 1987 in southern Vietnam. Neolaurnaudia phymatodes was poorly knownsince the original description, and is, thus, re-described here. This species can be distinguished from all other Neolarnaudia species by a suite of characters; carapace broader, frontal area with many granules, supraorbital margingranulated, suborbital and pterygostomian regions and merus of third maxillipedcovered with many granules, terminal segment of Gonopod 1 strongly curved inwards and covered with many pubescences, lateral margin of telsonstrongly concaved. Citation: Do Van Tu, Dang Van Dong, Le Van Tho, Phan Doan Dang, 2017. Review of two genera of freshwater crabs, Larnaudia Bott, 1966 and Neolarnaudia Türkay Naiyanetr, 1987 (Crustacea: Decapoda: Potamidae) with redescription Neolarnaudiaphymatodes (Kemp, 1923) from Southern Vietnam. Tap chi Sinh hoc, 39(4): 398-405. DOI: 10.15625/0866-7160/v39n4.8464.*Corresponding author: [email protected], [email protected] 19 September 2017, accepted 12 December 201