Distance Education (DE) theorists have argued about the requirement for a theory to be comprehensive in a way that can explicate many of the activities associated with DE. Currently, Transactional Distance Theory (TDT) (Moore, 1993) and the Theory of Instructional Dialogue (IDT) (Caspi & Gorsky, 2006) are the most prominent theories, yet they still do not represent a unified and comprehensive theory for DE. This paper provides a review of the existing literature on DE theories and identifies potential gaps in theorising distance education. Building on Giddens’ (1984) work, an innovative approach to theorising DE is proposed through the conceptualisation of the Adapting Structuration Theory In Distance Education (ASTIDE) model as a means to explicate DE operations and practices at the institutional and national/international level. It also presents evidence, from a larger study, of the necessity of a comprehensive model such as the ASTIDE constructed through an investigation into the DE systems of developing and developed countries.
Coronary heart disease (CHD) is a complex and heterogeneous cardiovascular disease. There are many genome-wide association studies (GWAS) performed worldwide to extract the causative genetic factors. Moreover, each population may have some exceptional genetic characteristic. Thus, the background of our study is from the previous Lithuanian studies (the LiVicordia Project), which demonstrated the differences of the atherosclerosis process between Lithuanian and Swedish male individuals. In this study we performed GWAS of 32 families of Lithuanian origin in search of significant candidate genetic markers [single nucleotide polymorphisms (SNPs)] of CHD in this population. After careful clinical and biochemical phenotype evaluation, the ~770K SNPs genotyping (Illumina HumanOmniExpress- 12 v1.0 array) and familial GWAS analyses were performed. Twelve SNPs were found to be significantly associated with the CHD phenotype (p value <0.0001; the power >0.65). The odds ratio (OR) values were calculated. Two SNPs (rs17046570 in the RTN4 gene and rs11743737 in the FBXL17 gene) stood out and may prove to be important genetic factors for CHD risk. Our results correspond with the findings in other studies, and these two SNPs may be the susceptibility loci for CHD
Ho Chi Minh City (HCMC), the largest city in Vietnam, is steadily growing, certainly towards a mega city in the near future. Like other mega cities at the boom stage, it has to face with serious environmental matters insolvable for many years. The situation may be worse under the effects of global climate change, geological subsidence due to non-standard construction and sea level rise. The situation of HCMC can be damaged or even broken by resonant effects of unsolved environmental matters and latent impacts of climate change. This article shows the challenges to the urban sustainable development under the duo effect of urban environmental matters and climate change in Ho Chi Minh City. Opportunities and strategic directions to overcome the challenges are also analyzed and recommended.
This paper uses the gvSIG 2.2.0 software, IDW interpolation method, river and stream network data, and 36 sampling sites to build the maps of three monitored parameters such as pH, water temperature, and salinity in the Lower Dong Nai River system (2009-2010) in dry season. Based on an analysis of these maps and statistical assessment by using the R software, the correlations between pH, temperature, and salinity are clarified. The results show that the pH and temperature values have a tendency to decrease, whereas the salinity tends to increase annually. The pH value has good and significant correlations with the water temperature and salinity in both simple and multiple linear regression models. The results aim to provide a scientific reference for further research on the water environment in this area.
In accordance with Decision 99/TTg dated 9/2/1996 and Decision 173/TTg dated 6/11/2001 of the Prime Minister regarding the construction program of residential clusters (residential flood free areas), these residential areas as constructed would be fully equipped with critical infrastructures and services such as water supply and drainage works, toilets with sanitary appropriateness, etc. to ensure environmental sanitary conditions in the residential clusters. However, the actual surveys done in residential clusters in the Mekong Delta show that many arising problems must be addressed to enable the local communities to have better living conditions and ensure the sanitary conditions and environmental safety.
This study to enhance the discussion about the usefulness of benthic macroinvertebrates for water quality assessment in Saigon River and its tributaries. Data from 16 sites were used as a representative example for Saigon River and its tributaries in the area of basin over 4,500 km2, the length through provinces of Tay Ninh, Binh Phuoc, Binh Duong, and Ho Chi Minh City of about 280 km. The data covered the period of dry and rainy seasons in 2015, the survey sampled 16 sites (32 events) of the Saigon River and its tributaries selected. To implement this evaluation, the analyses were based on MRC methods and classifications these improved by the scientific group.
The analysis of general characteristics of benthic macroinvertebrates and bio-indices were used to examine the spatial patterns of water quality and biological groups. The value of good water quality was recorded in the sites far from industrial parks, crowded citizen areas, big cities (SG1 and SG2) while the sites in near urban Ho Chi Minh City and Thu Dau Mot Town or industrial areas (the section of Saigon River from SG6 to SG13) where had the value of worse water quality because of the more human activities. Especially, there was not any animal that was collected in the site SG7 because of too heavy pollution. The results demonstrated that these organisms could be applied to describe the ecological health in the Saigon River and its tributaries.
Activated sludge acclimated to 2,4-D was used to degrade 2,4-D in batch reactions. Biogenic substrates of sucrose and peptone, in varying concentrations, separately and combined, were supplemented to the degradation reactions to find if, how and why biogenic supplementations were beneficial to the degradation of the xenobiotic. With the biogenic supplement as a variable and other reaction conditions, optimal constant supplementation schemes were found which suit as feasible ways for enhancing the degradation rate of 2,4-D. Among the number of supplementation combinations, the ones having optimal advantage were 50 mg/L of sucrose, 80 mg/L of peptone, each separately, and 20 mg/L sucrose and 40 mg/L peptone combined.
This study aims to enhance the discussion about the usefulness of invasive animals for biodiversity assessment in Mekong Delta provinces. Data were used for the area of 5.331 km2 in Ca Mau Province . The data covered the period 2017 – 2018. To implement this evaluation, the analyses were based on the scientific documents “Introduction to Invasive Species in Vietnam” of Vietnam Agency of Biodiversity Conservation and “The Aquatic Invasive Species Assessment and Management Plan” Massachusetts Department of Conservation and Recreation, and the working experiences of research group for the invasive species assessment [2, 3]. The results found two invasive animal species such as apple snail – Pomacea canaliculata (Lamarck, 1819) and Amazon sailfin catfish – Pterygoplichthys pardalis (Castelnau, 1855) . These species mapped in the map of Ca Mau Province. The problem of invasive species has become an important issue of concern for the local government and community. However, if appropriate targets for ecosystem management planning is suggested, these “invaders” can be prevented the spread of invasive species.
Rural people in the Mekong Delta (MD) use surface water from rivers and canals for daily activities; and in areas far from the canals, people use rainwater for cooking and drinking. In certain areas, people use shallow layered groundwater and deep layered groundwater from drilled wells 80m – 100m deep. The quality of water used in daily activities of rural people is almost uncontrolled. Somewhere water supply systems are used, but they have been built over many periods, certain ones for over 50 years ago, thus having a lot of damage and many deposits, causing loss of pressure and huge loss of water. The issue of repairing, replacing and installing more water supply networks in urban areas is facing lots of financial, technical difficulties.
The precise rainfall estimate with appropriate spatial and temporal resolutions is a key input to distributed hydrological models. However, networks of rain gauges are often sparsely distributed in developing countries. To overcome such limitations, this study used some of the existing gridded rainfall products to simulate streamflow. Four gridded rainfall products, including APHRODITE, CFSR, PERSIANN, and TRMM, were used as input to the SWAT distributed hydrological model in order to simulate streamflow over the Srepok River Catchment in Vietnam. Besides that, the available rain gauges data were also used for comparison. Amongst the four different datasets, the TRMM and APHRODITE data show their best match to rain gauges data in simulating the daily and monthly streamflow with satisfactory precision in the 2000-2006 period. The result indicates that the TRMM and APHRODITE data have potential applications in driving hydrological model and water resources management in data-scarce and ungauged areas in Vietnam.