Coagulation of chitin production wastewater from shrimp scraps with by-product chitosan and chemical coagulants

[[abstract]]Chitin production wastewater contains nutrient-rich organic and mineral contents. Coagulation of the wastewater with a natural coagulant such as by-product chitosan would be an economical and environmentally friendly method of treatment. This study investigated the treatment efficiencies of a preliminary sedimentation process followed by coagulation. The removal efficiencies for wastewater parameters were evaluated and compared for coagulants including by-product chitosan, polyaluminum chloride, and polyacryamide. The evaluation was based on the removal of wastewater turbidity and other criteria, including tCOD, sCOD, TKN, NH4+–N, TP, TSS, calcium, and crude protein. The results showed that the preliminary sedimentation (before coagulation) can remove over 80% of turbidity and more than 93% of TSS at pH 4 in 30 min. At optimal conditions, when the ratio of crude protein and calcium was 4.95, by-product chitosan dose of 77.5 mg·L−1 and pH = 8.3, the wastewater characteristics changes were tCOD 23%, sCOD 32%, TKN and ammonium 25%, TP 90%, TSS 84%, Ca2+ 29%, and crude protein 25%. The residue recovered through coagulation consists of up to 55 mg·g−1 crude protein, which is used for animal feed or crop fertilizer.[[sponsorship]]科技部[[notice]]補正完

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

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

Vietnam's visa policy for tourists

States employ travel visa as an instrument to leverage on visitor arrivals for various reasons. In tourism, visa plays a crucial role in facilitating potential and last-minute tourists’ decision making process. This paper focuses on the Vietnamese government’s visa policy in the context of tourism development. Adopting an economic approach, this paper reviews key achievements in tourist immigration policies and examines the challenges that deter tourists from visiting the country. This study purports that a stronger national strategy pertaining to simplification of visa processing and streamlining common visa entry union with neighboring countries within the AEC 2015 framework will translate to gains for Vietnamese tourism. __________________________________________________ Key words: economic approach, national visa policy, tourism developmen

GC-MS analysis and cytotoxic activity of the n-hexane fraction from Curcuma sahuynhensis Škornick. & N.S.Lý leaves collected in Vietnam

Curcuma sahuynhensis Škornick. & N.S.Lý is an endemic plant in Vietnam that has been used by the Sa Huynh people as a spice and medicine to cure illnesses linked to digestive disorders. Very little information is available so far about the chemical composition and biological effects of C. sahuynhensis. To find new pharmaceutical ingredients, the in vitro cytotoxic effect and the chemical profile of C. sahuynhensis leaf extract were investigated. In this study, the percolation method and liquid-liquid dispersion technique were used to extract dry sample powder. The chemical composition was detected by gas chromatography-mass spectrometry (GC-MS). The Sulforhodamine B and MTT methods were used to determine the cytotoxic activity. The chemical composition analysis showed that the leaf extract contained 14 components. The major components in the n-hexane extract were 6,10,14-trimethylpentadecan-2-one, phytol, 1-ethylbutyl hydroperoxide, isoborneol, 1-methylpentyl hydroperoxide, and neophytadiene. On human cancer cell lines, namely MFC-7, SK-LU-1, Hela, MKN-7, and HL-60, the leaf extract showed dose-dependent cytotoxic activity, with IC50 values ranging from 221.70±10.24 to 369.42±10.60 ?g/mL. The present study provides significant information on the chemical components and cytotoxic effects of the n-hexane extract from C. sahuynhensis leaves. The findings will continue to be crucial in future research on the evaluation of secondary metabolite compound analysis for cancer therapeutic effects

Recent geodynamic characteristics of the Southern Central coast and the relations with geological hazards

Recent geodynamic characteristics of the Southern Central coast are analyzed on the basis of vertical and horizontal displacement velocities along active fault zones. The horizontal displacement velocity varies in magnitude from this fault system to another fault system, from 0.11–0.3 mm/year on the strike-slip - normal faults to 0–0.058 mm/year on the strike-slip faults and normal faults. The subsidence velocity changes complicatedly, different from one fault to another fault, depending on the mechanism of faults. On the continental shelf, most of the values of high subsidence’s velocity are related to the normal and strike-slip faults. Subsidence activities make the sea level increase highly, the subsidence activity makes the sea level rise at structures that fall close to the shore, reach about 0.2–0.48 mm/year in late Pleistocene - Holocene. The increase of sea level directly affects the intensity of erosion, flood, salinity and land loss events in coastal lowlands. Slippage of the seabed, earthquakes, volcanoes are geological hazards directly related to the geodynamic regime of the Southern Central coast

THÀNH LẬP SƠ ĐỒ PHÂN BỐ ĐỨT GÃY KHU VỰC BIỂN VEN BỜ NAM TRUNG BỘ TRÊN CƠ SỞ MINH GIẢI TÀI LIỆU ĐỊA CHẤT - ĐỊA VẬT LÝ

The scheme of the faults in South Central coastal region was established on the basis of interpreting the high resolution shallow seismic data and the deep-seismic data, in combination with the previous studies on geodynamics, tectonic evolution, geological hazards of the South Central coastal region. The fault systems were formed based on updated geophysical, geomorphological, tectonophysic and remote sensing data, including 19 faults in 3 directions: Sub-longitudinal (8 faults), NE-SW (7 faults) and NW-SE (4 faults).Sơ đồ phân bố đứt gãy khu vực biển ven bờ Nam Trung Bộ được thành lập trên cơ sở minh giải, phân tích tài liệu địa chấn nông phân giải cao, địa chấn dầu khí, kết hợp và kế thừa các kết quả nghiên cứu địa chất-địa động lực, tiến hóa kiến tạo. Hệ thống đứt gãy được nghiên cứu, chính xác hóa từ các tài liệu địa vật lý, địa chất-địa mạo, vật lý kiến tạo, viễn thám mới nhất. Trong khu vực có 19 hệ đứt gãy, phát triển theo 3 hướng chính là á kinh tuyến (8 hệ đứt gãy), đông bắc -tây nam (7 hệ đứt gãy) và tây bắc - đông nam (4 hệ đứt gãy)

Impact of climate change on meteorological, hydrological and agricultural droughts in the Lower Mekong River Basin: a case study of the Srepok Basin, Vietnam

peer reviewedThe objective of this study is to assess future changes in meteorological, hydrology and agricultural droughts under the impact of changing climate in the Srepok River Basin, a subbasin of LMB, using three drought indices; standardized precipitation index (SPI), standardized runoff index (SRI) and standardized soil moisture index (SSWI). The well-calibrated Soil and Water Assessment Tool (SWAT) is used as a simulation tool to estimate the features of meteorological, hydrological and agricultural droughts. The climate data for the 2016–2040 period is obtained from four different regional climate models; HadGEM3-RA, SNU-MM5, RegCM4 and YSU-RSM, which are downscaled from the HadGEM2-AO GCM. The results show that the severity, duration and frequency of droughts are predicted to increase in the near future for this region. Moreover, the meteorological drought is less sensitive to climate change than the hydrological and agricultural droughts; however, it has a stronger correlation with the hydrological and agricultural droughts as the accumulation period is increased. These findings may be useful for water resources management and future planning for mitigation and adaptation to the climate change impact in the Srepok River Basin

Diet quality in childhood: the Generation R Study

Purpose: We aimed to evaluate diet quality of 8-year-old children in the Netherlands, to identify sociodemographic and lifestyle correlates of child diet quality, and to examine tracking of diet quality from ea