194 research outputs found

    Peatmass Change and Water Level Influencing Regenerated Melaleuca Forest after a Fire in U Minh Thuong National Park, Vietnam

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    Following the largest forest fire in Vietnam in 2002, various activities were undertaken to sustain the mangrove forest on peat soil remnants in the Mekong Delta region. These activities included promoting natural regeneration, afforestation, and rapid forest restoration measures, in addition to other protective measures such as rainwater retention to maintain moisture levels for fire prevention. However, two critical challenges emerged: allowing the forest to naturally regenerate would lead to annual forest fires but maintaining a constant water level through year-round water retention would harm biodiversity. The study was conducted in U Minh Thuong National Park to address forest regeneration. After a major forest fire in Vietnam, various measures were taken to promote forest regeneration, including afforestation, silvicultural solutions, and hydrological techniques such as rainwater storage to maintain humidity and prevent future fires. A hand drill was used to collect samples, and a total of 15 plots were set up to survey the growth of the forest at three peat thickness levels. At each of the three collection sites, samples of one kg were collected and labeled according to the site as UTM1, UTM2, and UTM3. The samples were then sent to the laboratory of the Southern Institute of Forestry Science for analysis. There was a relationship between the chemical indicators of peat and the evolution of the Melaleuca forest. Peat thickness and flooding regime significantly influenced the growth of the Melaleuca forest, while another identified relationship was between peat chemical indicators and forest growth. The chemical composition of peat water changed significantly due to the rainy and dry seasons, with nutrient content and pH affecting forest growth. Peat thickness and flooding regime were essential in regulating forest growth. These studies highlight the importance of considering multiple factors, such as peat thickness and chemical properties, when developing effective forest restoration strategies. By understanding the relationship between peat thickness, chemical properties, and forest growth, forest managers can develop targeted strategies to promote regeneration while minimizing negative impacts on biodiversity

    An Efficient Method for Generating Synthetic Data for Low-Resource Machine Translation – An empirical study of Chinese, Japanese to Vietnamese Neural Machine Translation

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    Data sparsity is one of the challenges for low-resource language pairs in Neural Machine Translation (NMT). Previous works have presented different approaches for data augmentation, but they mostly require additional resources and obtain low-quality dummy data in the low-resource issue. This paper proposes a simple and effective novel for generating synthetic bilingual data without using external resources as in previous approaches. Moreover, some works recently have shown that multilingual translation or transfer learning can boost the translation quality in low-resource situations. However, for logographic languages such as Chinese or Japanese, this approach is still limited due to the differences in translation units in the vocabularies. Although Japanese texts contain Kanji characters that are derived from Chinese characters, and they are quite homologous in sharp and meaning, the word orders in the sentences of these languages have a big divergence. Our study will investigate these impacts in machine translation. In addition, a combined pre-trained model is also leveraged to demonstrate the efficacy of translation tasks in the more high-resource scenario. Our experiments present performance improvements up to +6.2 and +7.8 BLEU scores over bilingual baseline systems on two low-resource translation tasks from Chinese to Vietnamese and Japanese to Vietnamese

    Competencies of the Team of Department Head at Higher Education Institutions in Vietnam in The Context of the Industrial Revolution 4.0

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    This study aims to investigate the Competencies of the team of department head at higher education institutions in Vietnam to implement higher education development in the context of the industrial revolution 4.0. The authors conducted a Delphi study with 15 experts in educational management in Vietnam to gather their expert views on the competencies of the team of department head at higher education institutions. A total of 24 components of competency related to 4 fields (professional expertise, scientific research, subject management and leadership, social activities and international cooperation) were strongly emphasized by experts. The competence of the team of department head is proposed based on the ideas of a group of experts and the results need to be tested, completed and confirmed by follow-up work. Besides, in this study, we have not determined the level of achievement of each competence as well as developed assessment tools. The specific competencies of the team of department head can be considered as a foundation to contribute to the development of higher education in the context of the industrial revolution 4.0. We know that competence does not exist independently; in stead of, they should be considered in the specific context of teaching, university, culture and society. This study is one of the studies related to the competence contextualization of the team of department head at higher education institutions in the Vietnamese context

    SEASONAL VARIATION OF PHYTOPLANKTON FUNCTIONAL GROUPS IN TUYEN LAM RESERVOIR, CENTRAL HIGHLANDS, VIETNAM

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    Seasonal changes in freshwater phytoplankton assemblages at Tuyen Lam Reservoir in the Central Highlands of Vietnam were classified into 23 functional groups based on physiological, morphological, and ecological characteristics. A total of 168 species were recorded during 10 surveys from 2015 to 2019 at 7 sampling sites, with Chlorophyta dominating in number of species. Phytoplankton abundance varied from 0.18×105 to 21.2×105 cells/L during the study period, mainly due to cyanobacteria. Seven of the 23 functional groups were considered to be dominant (relative density > 5%).  The dominant functional groups were groups M and G in the dry season and groups M, G, P, and E in the rainy season. Group M (Microcystis aeruginosa) was the most common in both seasons, while group P (Closterium, Staurastrum, Aulacoseira), group E (Dinobryon, Synura), and group G (Sphaerocystis, Eudorina) were more common in the rainy season. The Shannon diversity index (H¢) showed that phytoplankton communities were relatively diverse and that most of the study sites were lightly polluted. However, the ecological status has deteriorated at some locations due to the overgrowth of group M, leading to eutrophication in this reservoir. This study highlights the usefulness of functional groups in the study of seasonal changes in phytoplankton dynamics. Functional groups are applied for the first time at Tuyen Lam Reservoir and can be used to predict early-stage cyanobacterial blooms in future studies

    Serum interleukin 6 concentration in patients with pemphigus

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    Pemphigus is a rare autoimmune blistering disease that detrimentally affects the integumentary system and decreases patients’ quality of life. Recent studies have shown that interleukin 6 (IL-6) is closedly involved in the immunophathogenesis of pemphigus. Therefore, this study was performed to evaluate the role of IL-6 in the pathogenesis and severity of pemphigus disease. The case-series study was conducted in Ho Chi Minh City Hospital of Dermato-Venereology from January 2022 to August 2022, involving 26 patients with pemphigus vulgaris (PV), 4 patients with pemphigus foliaceus (PF), and 20 healthy volunteers. The serum IL-6 concentrations of patients with PV and PF were significantly higher than those of the healthy volunteers (P < 0.001). Serum IL-6 concentrations were significantly higher in patients with a positive than a negative Nikolsky sign (P < 0.001). A significant correlation was found between the serum IL-6 concentration and the pemphigus disease area index (r = 0.8, P < 0.001). Our results suggest that IL-6 may play an important role in the pathogenesis and severity of pemphigus. Therefore, new therapies targeting IL-6 may be a promising choice for treating pemphigus, especially in its severe forms

    Tuning Electronic Transport Properties of Zigzag Graphene Nanoribbons with Stone-Wales Defect

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    Influences of the symmetric Stone-Wales (SW) defect on the electronic transport properties of the zigzag graphene nanoribbons (ZGNRs) has been studied using ab\it{ab} initio\it{ initio} simulation based on density functional theory (DFT) combined with non-equilibrium Green's function (NEGF) technique. The calculated transmission spectra T(E) at various bias windows, device densities of states (DDOS), current characteristics as well as local density of states (LDOS) of the defective asymmetric and symmetric ZGNRs are presented in comparison of those for the pristine ZGNRs. It has been established the metallic character of the electronic transport in asymmetric ZGNRs, and in symmetric ones, the current has a semiconductor behavior, with negative differential resistance (NDR) effect. Symmetric SW defect, as a most unfavorable SW defect type for electric conductance, remarkably decreases the current values, but does not change the character of conductivity in both the asymmetric and symmetric ZGNRs. NDR has been explained by the altering by SW defect the number of frontier molecular orbitals entering bias windows

    Graphene Effect on Efficiency of TiO2-based Dye Sensitized Solar Cells (DSSC)

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    Colloidal paste of TiO2 embedded with graphene (GS) was fabricated and used to spread TiO2_2 film photo-electrode of DSSC solar cells. The dye N179 and Iodine-based electrolyte were used in the DSSC solar cells. Raman scattering, SEM images were used to identify the material phases and microstructure of the film photo-electrode. I/V characteristics of the DSSC cells were recorded at room temperature. Open-circuit voltage Voc, short-current JscJ_{sc} and efficiency η of the DSSC cells were estimated. It shows that graphene addition has affected on VocV_{oc},JscJ_{sc} and η\eta. The VocV_{oc},JscJ_{sc} and η\eta abnormally depend on graphene content. The efficiency reached a maximal value with graphen concentration of 0.005 wt %, after that decreased. It is supposed to be related with an improving the charge transfer in the working photo-electrode of DSSC

    The Relationship between Public Debt, Budget Deficit, and Sustainable Economic Development in Developing Countries: The Role of Corruption Control

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    This study investigates the effects of public debt and budget deficits on the sustainable economic development of developing countries, taking into account the role of control of corruption. The two-step GMM method was applied for unbalanced panel data of 59 developing countries from 2004 to 2015. The study found that public debt and the budget deficit had negative effects on sustainable development, while the effect of control of corruption was positive. Moreover, using interaction terms between control of corruption and public debt and budget deficit, respectively, empirical results showed that controlling corruption limited these adverse effects. Thus, if the objective is to achieve sustainable economic development, developing countries should not see raising public debt or maintaining budget deficits as a strategy for economic development. The study contributes empirical evidence to the theory of debt overhang, crowded effects, and institutional theory in the context of developing countries. The implications are also discussed in this paper

    Antibacterial Nanocomposites Based on Fe 3

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    For the vulcanized natural rubber (NR), incorporation of silver nanoparticles (AgNPs) into the NR matrix did not exhibit the bactericidal property against Escherichia coli (E. coli). However, incorporation of AgNPs into polyethylene (PE) matrix showed good antibacterial activities to both Gram-negative and Gram-positive bacteria. In the present work, NR/PE (85/15) blends have been prepared by melt blending with presence of compatibilizer in an internal mixer. To possess antibacterial property, AgNPs (5–10 nm) or Fe3O4–Ag hybrid nanoparticles (FAgNPs, 8 nm/16 nm) were added into PE matrix before its blending with NR component. The tensile test indicated that the presence of compatibilizer in NR/PE blend significantly enhanced the tensile strength and elongation at break (up to 35% and 38% increases, resp.). The antibacterial activity test was performed by monitoring of the bacterial lag-log growth phases with the presence of nanocomposites in the E. coli cell culture reactor. The antibacterial test showed that the presence of FAgNPs in NR/PE blend had a better antibacterial activity than that obtained with the lone AgNPs. Two similar reasons were proposed: (i) the faster Ag+ release rate from the Fe3O4–Ag hybrid nanoparticles due to the electron transfer from AgNP to Fe3O4 nanoparticle and (ii) the fact that the ionization of AgNPs in hybrid nanostructure might be accelerated by Fe3+ ions

    Tannins: Extraction from Plants

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    The chapter presents mainly on different extraction methods of tannin. Some technical means required for effective extraction are also presented, for example, collection and treatment of plant and drying and storage of plant. Opportunity and challenges in application of extraction methods are also exhibited in the chapter
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