Abstract: The occurrence of cyanobacterial blooms (CYBs) associated with cyanotoxins has been reported worldwide. While planktonic cyanobacteria and the contamination of microcystin (MC) in the water column have been the subject of many investigations, little attention is paid to the benthic cyanobacterial communities and MC concentration in the benthic environment. This study aimed to investigate the benthic cyanobacterial composition and MC concentration accumulated in sediment from the Tri An Reservoir (TAR), Dong Nai province. Benthic cyanobacterial communities and sediment were collected at five sites in dry and rainy seasons. The benthic cyanobacterial communities were morphological observation and identification. Different nitrogen, phosphorus species, and chlorophyll-a (Chl-a) in sediment were analyzed. MCs concentration in sediment was quantified by High-Performance Liquid Chromatography (HPLC). Results indicated that the sediment from the TAR was contaminated with nitrogen. A total of 19 species belonging to 12 genera, 3 orders of cyanobacteria were identified. In which, Anabaena, Oscillatoria, and Microcystis were the three most commonly found in the samples. Surface sediment samples contained high densities of colonial Microcystis. The Chl-a concentration in sediment in dry and rainy seasons ranged from 1.96–3.45 and 0.71–3.15 µg/g fresh weight (FW), respectively. MC was detected in sediment at all sites in both dry and rainy seasons with a concentration up to 191.4±14.2 ng/g FW. The outcome of this study provides basic knowledge on MC and potential MC-producing cyanobacteria in a drinking water supply. Further investigation on the toxic producing ability of the benthic cyanobacteria species from the Tri An Reservoir is required.

Abstract: Colletotrichum species cause anthracnose in various tropical crops in both cultivation and postharvest periods. The current synthetic fungicides to treat anthracnose sometime show toxic effects for farmers, residues on foods, and environmental impacts. In this work, turmeric extract containing curcuminoids was used as an active ingredient and formulated into a nanoemulsion to control anthracnose in red pepper and tomato fruits. The nanoparticles containing turmeric extract (25 %) were successfully prepared by encapsulation using Tween-80 and PEG 400 as emulsifiers. Out of the three main curcuminoids in the turmeric extract, BDMC was determined as the most abundant constituent via HPLC analysis. Turmeric nanoparticles showed an average particle size of 203 nm, polydispersity index (PI) of 0.322, and zeta potential of -92.7 mV.  In the in vitro antifungal bioassay, this nanoformulation significantly inhibited the mycelial growth of Colletotrichum gloeosporioides and Colletotrichum orbiculare in a dose-dependent manner. Red pepper anthracnose was also consistently suppressed by turmeric nanoparticles but the tomato anthracnose was resistant to this formulation at 10 mg/mL in vivo. The study results proved the effectiveness of turmeric nanoparticles to control red pepper anthracnose in postharvest preservation and suggested developing the innovative nanoformulation as a green fungicide.

Abstract: Flood models based on traditional hydrodynamic modeling encounter significant difficulties with real-time predictions, require enormous computational resources, and perform poorly in data-limited regions. The difficulties are compounded as flooding worldwide worsens due to the increasing frequency of short-term torrential rain events, making it more challenging to predict floods over the long term. This study aims to address these challenges by developing a rapid flood forecasting model combining machine learning algorithms (support vector regression, XGBoost regression, CatBoost regression, and decision tree regression) with hydrodynamic modeling in Quang Tri province in Vietnam. 560 flood depth locations were obtained by hydrodynamic modeling, and several locations measured in the field were used as input data for the machine learning models to build a flood depth map for the study area. The statistical indices used to evaluate the performance of the four proposed models were the receiver operating characteristic (ROC) curve, area under the ROC curve, root mean square error, mean absolute error, and coefficient of determination (R2). The results showed that all four models successfully constructed a flood depth map for the study area. Among the four proposed models, CatBoost regression performed best, with an R² value of 0.86. This was followed by XGBoost regression (R²=0.84), decision tree regression (R²=0.72), and then support vector regression (R2=0.7). This integration of hydrodynamic modeling and machine learning complements the framework in much of the existing literature. It can provide decision-makers and local authorities with an advanced flood warning tool and contribute to improving sustainable development strategies in this and similar regions.

Abstract: Zanthoxylum avicennae (Lam.) DC. is a medicinal and aromatic plant, belong to the Zanthoxylum genus. The plant is found in some Asian contries, including Viet Nam. The various parts of this plant has been used to medicine and contain essential oils. In this study, the essential oil of Z. avicennae was isolated. Two essential oils from the leaves and twigs of Zanthoxylum avicennae (Lamk.) DC. collected from a limestone forest in Northern part of Vietnam were separately obtained by hydrodistillation and analyzed by GC-MS. A total of 42 and 53 compounds were identified in the leaf and twig oil, respectively. Mono- and sesquiterpenes were found to be the main chemical classes in both oils. Major constituents of the leaf oil were β-caryophyllene (18.71 %), α-humulene (14.03 %), α-terpinene (10.65 %), γ-terpinene (10.64 %), and linalool (9.42 %). Major constituents of the twig oil were linalool (18.3 %), β-phellandrene (8.82 %), α-terpinene (7.85 %), o-cymene (7.79 %), γ-terpinene (7.99 %), and (E)-β-ocimene (6.62 %). In the leaf oil the total amounts of mono- and sesquiterpenes were nearly equal (49.15 % and 44.27 %, respectively), while the twig oil was dominated by monoterpenes (76.66 % and 2.65 %, respectively). Previous literature data on essential oils obtained from this plant species were reviewed and discussed.

Abstract: The H'mong short tail dog is breed indigenous dogs, distributed in mountainousareas of northern Vietnam. H'mong short tail dog possesses many valuable properties such as intelligence, agility, good health, good shape, human friendliness, ease of training and it can fully meet the needs of war Dogs intelligence, strength, good parenting, people friendly and more importantly, still keeping wild characteristics of hunting dogs. The total 45 samples (blood) collected from 45 individuals in two provinces of Northern Vietnam (Ha Giang and Lao Cai), were used to assess genetic diversity based on sequencing hypervariable – 1 region (HV1) in D-loop genes. In the current study showed that genetic diversity of H'mong short tail dog was high with nucleotide diversity (Pi = 0.00801), haplotype diversity (Hd = 0.96162) and average number of nucleotide differences (Kt = 5.18384). Furthermore, 25 different haplotypes were recorded and divided into four main groups: A, B, C, and E. Of which, seven new haplotypes in haplogroups A (An1 to An7) and 18 haplotypes have been published in the world. In addition, H'mong short tail dog was found rare haplogroups (B1, C2, E1 and E4). Notably, there is none individuals contain haplotype of haplogroups (D and F). H'mong short tail dog were identified 38 single nucleotide polymorphisms, including 32 nucleotide base substitution/base insertion and 6 nucleotide indel mutation. Almost mutation was transversion (31/32) and only one nucleotide transition mutations. Phylogenetic tree shown that H'mong short tail dog have close relationship with dogs origin from East Asia (China, Japan and Korea).

Abstract: We propose a novel principle of determination of fiber Bragg grating (FBG) wavelength shift which is impacted by a variation of physical parameters such as temperature, pressure and/or strain. In common case the wavelength shift of FBG was monitored by wavelength measurement using a high-cost spectrometer and a broad band light source. In our proposed technique the wavelength shift of FBG can be determined by change of lasing wavelength of distributed feedback laser (DFB-laser) due to the change of laser substrate temperature. The maximal opto-electrical intensity of photodetector would be obtained when the laser wavelength and FBG reflection wavelength are coincided. The FBG sensor prototype has shown excellent response for laser temperature change in the range of \(10^{\circ}C-50^{\circ}C\) with the ratio \(\Delta \lambda /\Delta T\) of the DFB laser is of 77.5 pm.K\(^{ - 1}\). Key features of the proposed technique are fabrication of low-cost FBG sensors for civil engineering.

Abstract: The paper presents the initial results of the study of volcanic cave system and its typical formations in Krongno Volcano Geopark (KVG), Dak Nong, Vietnam. The volcanic caves have been discovered since 2007, under UNESCO sponsored the scientific project, are seen as unique geological heritages. The collaborative surveys and studies between Vietnamese geologists and the members of the Non-Profit Organization, Vulcanospeleological Society of Japan have discovered and surveyed 45 caves, and detailed mapping 20 caves. Using a complex of adequate methods, especially Remote Sensing image interpretation method, Surveying and mapping lava cave method, K/Ar dating isotopic analytical method and Current methodology, the studies aim to affirm endogenous origin of the lava cave system, the formation mechanism, as well as the typical formations of the caves. Up to date, the lava caves and interior formation in lava caves in KVG have been examined and evaluated in term of geological nature and recognized as pillar geological heritages of the Geopark.References Allred K., AllredC., 1997. Development and morphology of Kazumura Cave, Hawaii. Journal of Cave and Karst Studies, 59(2), 67-80.Allred K., Allred C., 1997. Tubular lava stalactites and other related segregations. Journal of Cave and Karst Studies, 60(3), 131-140.Barnabás Korbély, 2014. Diverse volcanic features as dominant landscape elements and pillars of geotourism in the Bakony-Balaton Geopark, Hungary. Abstract Book Workshop “Geoparks in volcanic areas: sustainable development strategies”, October 29th to November 1st, 2014. Terceira and Graciosa Islands, Azores Global Geopark, 35-38.Bird Deanne K., et al., 2014. Southern Iceland: Volcanoes, Tourism and Volcanic Risk Reduction.In Volcanic Tourist Destinations. Springer, Editors: Erfurt-Cooper, Patricia (Ed.). ISBN: 978-3-642-16190-2, 35-46. Cooper Malcolm J.M., 2014. Volcanic National Parks in Japan.In Volcanic Tourist Destinations. Springer, Editors: Erfurt-Cooper, Patricia (Ed.). ISBN: 978-3-642-16190-2, 231-246.Dave Bunnell, 2014. The virtual lava cave Created: August 4, 2000.Last update: December 16, 2014. Reviewed by Kevin & Carlene Allred. Available at: 〈 http://www.goodearthgraphics.com/virtual_tube/virtube.html). Date accessed: 02 May 2018.Gadányi P., 2010. Formation, types and morphology of basalt lava caves. PhD. thesises. University of Pécs Faculty of Natural Sciences Doctoral School of Earth Sciences, Hungary, 1-19.Gaki-Papanastassiou, Kalliopi, et al., 2014. Volcano Tourism in Greece: Two Case Studies of Volcanic Islands.In Volcanic Tourist Destinations. Springer, Editors: Erfurt-Cooper, Patricia (Ed.). ISBN: 978-3-642-16190-2, 69-87.Honda T., Tachihara H., 2015. Vietnam Volcanic Cave Survey. e-NEWSLETTER, UIS Commission on Volcanic caves, 69, 11-12. Honda T., Tinsley J.C., 2016. Classification of lava tubes from Hydrodynamic models for active lava tube, filled lava tube and drained lava tube. 17th International Vulcanospeleology symposium in Hawaii, USA. Sponsored by the Commission on volcanic caves of the International Union of Speleology.Larson C.V., 1991. Nomenclatures of lava tube features. 6th International Symposium on Vulcanospeleology in Hawaii. Published by the National Speleological Society, 231-248.Laumanns M., 2013. Important Lava Tube Caves found in Dong Nai Province Southern Vietnam. e-NEWSLETTER, UIS Commission on Volcanic caves, 67, 13. Machado M., Lima E., 2014. Geotourism and sustainable development partnerships in the Azores Geopark. Abstract Book Workshop “Geoparks in volcanic areas: sustainable development strategies”, October 29th to November 1st. Terceira and Graciosa Islands, Azores Global Geopark, 45-48.Moreira Jasmine Cardozo, et al., 2014.Tourism and Volcanism in the Canary Islands, Spain. In Volcanic Tourist Destinations.Springer, Editors: Erfurt-Cooper, Patricia (Ed.). ISBN: 978-3-642-16190-2, 47-55.Nelson S.A., 2017. Volcanoes and Volcanic Eruptions.EENS 1110. Physical Geology.Tulane University. New Orleans, USA.Nguyen Duc Thang (Ed.), 1989. Geology and Mineral Resources of Ben Khe - Dong Nai sheet at scale 1:200,000. General Department of Geology and Minerals of Vietnam. Hanoi. Nunes, João Caros., 2014. The Azores Archipelago: Islands of Geodiversity.In Volcanic Tourist Destinations. Springer, Editors: Erfurt-Cooper, Patricia (Ed.). ISBN: 978-3-642-16190-2, 57-67.Nunes João Caros., 2014. Azores Geopark volcanoes and volcanic landforms. Valuating the Azorean geodiversity and geosites through the geotourism. Abstract Book Workshop “Geoparks in volcanic areas: sustainable development strategies”, October 29th to November 1st. Terceira and Graciosa Islands, Azores Global Geopark, 41-43.Ogawa T., 1993. On lava caves in Japan and vicinity.Proceedings of the Third International Symposium on Vulcanospeleology, 56- 73.Patricia Erfurt-Cooper, 2014. Volcanic Geo-heritage.Sustainable Tourism Development in Volcanic Regions: Geoparks, National Parks and World Heritage Sites. Abstract Book Workshop “Geoparks in volcanic areas: sustainable development strategies”, October 29th to November 1st. Terceira and Graciosa Islands, Azores Global Geopark, 23-25.Peterson D.W., Holcomb R.T., Tilling R.I., Christiansen R.L., 1994. Development of lava tubes in the light of observations at Mauna Ulu, Kilauea Volcano, Hawaii. Bulletin of Volcanology, 56, 343-360. 

Abstract: In this paper, we present detail data of Pliocene - present tectonics and strain rate from GPS measurement and seismic interpretation. Using international reference frame ITRF08, we revealed absolute tectonic velocities of GPS sites with the slip rate to the east between 22 to 25 mm/year, to the south between 4 to 8 mm/year. The present strain rate was determined from present tectonic velocities that were consistent with the recent strain rates determined from seismic profiles, thickness of Pliocene - Quaternary sediments. Present day strain rate varying from 10 to 30 nano per year indicated that the region has been deformed weakly, in a stable tectonic regime.

Abstract: The Dempster-Shafer (DS) theory of evidence is frequently used to combine multipe supervised machine learning models into a robust fusion-based model. However, using the DS theory to create a fusion model from multiple one-class classifications (OCCs) for network anomaly detection is a challenging task. First, the lack of attack data leads to the difficulty in estimating an appropriate threshold for the OCC models to distinguish between normal and abnormal samples. Second, it is also very challenging to find the weight of OCCs that corresponds to the contribution of each OCC model in the fusion model. In this paper, we attempt to solve the above issues in order to make the DS theory applicable for constructing OCC-based fusion models. Specifically, we propose two novel methods for automatically choosing the appropriate threshold of OCCs and for estimating the weight of individual OCCs in fusion-based models. Thanks to that, we develop an One-class Fusion-based Anomaly Detection model (OFuseAD) from multiple single OCCs. The proposed model is evaluated on ten well-known network anomaly detection problems. The experimental results show that the performance of OFuseAD is improved on almost all tested datasets using two metrics: accuray and F1-score. The visualization results provides the insight into the characteristics of OFuseAD.