FIELD TEST ON CLEANING OF OIL POLLUTION ON NHATRANG BEACH OF VIETNAM

Joint Research on Environmental Science and Technology for the Eart

IDENTIFICATION OF SOME PREDOMINANT BACTERIA ISOLATED FROM JETA1 FUEL IN VIETNAM BY SEQUENCE ANALYSIS OF 16S RRNA GENE

Joint Research on Environmental Science and Technology for the Eart

EVALUATION OF SOLAR RADIATION ESTIMATED FROM HIMAWARI-8 SATELLITE OVER VIETNAM REGION

The development of Solar energy system is growing rapidly in Vietnam in recent years by encouragement of the Government in renewable energy. Requirement for accurate knowledge of the solar radiation reaching the surface is increasingly important in the successful deployment of Solar photovoltaic plants. However, measurements of different components of solar resources including direct normal irradiance (DNI) and global horizontal irradiance (GHI) are limited to few stations over whole country. Satellite imagery provides an ability to monitor the surface radiation over large areas at high spatial and temporal resolution as alternatives at low cost. Observations from the new Japanese geostationary satellite Himawari-8 produce imagery covering Asia-Pacific region, permitting estimation of GHI and DNI over Vietnam at 10-minute temporal resolution. However, accurate comparisons with ground observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 radiation product AMATERASS provided by JST/CREST TEEDDA using observations recorded at 5 stations in different regions of Vietnam. The result shows good agreement between satellite estimation and observed data with high correlation of range 0.92-0.94, but better in clear-sky episodes.Because of AMATERASS outperform, we used it for validating ERA-Interim reanalysis in the spatial scale. The comparison was made dividedly for 7 climate zones and 4 seasons. The conclusion is that ERA-Interim is also well associated with satellite-based estimates in seasonal trend for all season, but in average the reanalysis has negative bias towards satellite estimates. This underestimation is more pronounced in the months of JJA and SON periods and in the north part of Vietnam because of unpredicted cloud in the ERA reanalysis

Density estimates for the exponential functionals of fractional Brownian motion

In this note, we investigate the density of the exponential functional of the fractional Brownian motion. Based on the techniques of Malliavin’s calculus, we provide a log-normal upper bound for the density

Expression of Oryza sativa galactinol synthase gene in maize (Zea may L.)

Galactinol synthase (GolS) is a key biological catalyst for the synthesis of the raffinose oligosaccharides (RFOs) which play important roles in abiotic stress adaptation of plants, especially drought tolerance. GolS gene has been isolated on a variety of plants in order to create material resources for generating transgenic plants resistant to adverse environmental factors. In our previous research, we have isolated a GolS gene from drought stress cDNA library of Oryza sativa L. Moctuyen (named OsGolS). In this study, the expression vector pCAM-Rd/OsGolS carrying the isolated OsGolS gene under the control of stress-inducible Rd29A promoter was constructed and introduced into Agrobacterium tumefaciens LBA4404, which was used for maize transformation.  PCR and Real-time PCR assay indicated that transgene was integrated in the genome of the regenerated Zea mays plants. Reverse transcription-PCR showed that the OsGolS was transcribed into mRNA in Zea mays and was highly expressed. These results provide a basis for the study of the function of OsGolS in drought responses and for the development of drought stress tolerant crops.

Density estimates for the exponential functionals of fractional Brownian motion

In this note, we investigate the density of the exponential functional of the fractional Brownian motion. Based on the techniques of Malliavin’s calculus, we provide a log-normal upper bound for the density

Potential mitigation contribution from agroforestry to Viet Nam’s NDC

Viet Nam is among the 196 Parties in the Paris Agreement that has committed to low-emission development pathways. The country has formulated national climate change mitigation strategies that relate to forestry and agricultural sector, with a potential revision in 2019 that can include agroforestry (AF), provided that the potential mitigation contribution from this sector can be monitored and reported. This paper presents two approaches to measurement and reporting of AF, based on potential expansion domain (PED) of main AF systems in different regions across the country and the spatial distribution of trees outside forests (TOF), to estimate the potential mitigation contribution from AF, represented by total aboveground carbon (C) sequestration at national scale. Based on the PED approach, the total PED area of different AFs such as coffee, rubber or acacia-based, not including natural forest lands, is ≈10.1 million ha, or about 1/3 of the total land area in the country. Assuming the baseline land uses in the PED can be classified as “cultivated and managed lands,” which according to the Intergovernmental Panel on Climate Change (IPCC) has an average C stock 5 ton ha-1, expansion of the main AF systems across the country results in 262 ± 77 million tons of sequestered C per year, for ten years after plantation. The related total establishment cost for the expansion is USD 24.3 ± 11.3 billion. Using the TOF approach to estimate total tree coverage outside natural forest lands in 2010, total C storage of AF in Viet Nam is ≈355 million ton C, with an average of ≈21.8 ton C ha-1 from ≈20 million ha or about 2/3 of the total land area in the country. Comparing the PED and TOF approach under similar land coverage area of ≈10.1 million ha, the latter estimates a total C storage of ≈ 220 million ton C. By assuming it as total baseline C storage for the PED approach, the potential C gain from AF expansion is ≈92 million ton C, compared to ≈262 million ton C under the assumption of 5 ton ha-1 as average C stock for baseline land uses. This potential mitigation contribution from AF can be reported to relevant authorities, such as the Ministry of Agriculture and Rural Development (MARD) and its sub-institutions, that have a mandate to revise the potential mitigation contribution from the Agriculture and Land Use, Land Use Change, and Forestry sector to the country’s Nationally Determined Contribution (NDC). The challenges in integrating the potential contribution from AF to the agriculture sector or land use sector that focuses on forestry, or as a segregated land use category, should be further discussed with the relevant authorities