107 research outputs found

    ASSESSMENT OF GEOMORPHIC PROCESSES AND ACTIVE TECTONICS IN CON VOI MOUNTAIN RANGE AREA (NORTHERN VIETNAM) USING THE HYPSOMETRIC CURVE ANALYSIS METHOD

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    the Day Nui Con Voi (DNCV) area of Vietnam. For this purpose, a spatial database was collected and constructed, including DEM (Digital Elevation Model) and a geological map. The hypsometric curve (HC) analysis method and its statistical moments were adopted to use for the assessment. These methods have been widely used for the assessment of geomorphic processes and active tectonics in many areas in the world showing promising results. A total of 44 sub-basins of the Red River and the Chay river were analyzed. The result shows that 3 curve-types such as "straight- shape", "S- shape", and concave were found; with the concave curve being the dominant and widely distributed in the northeast side and in the south of the southwestern side of the study area. The hypsometric integral (HI) values are rather small with the largest value is 0.37 and the smallest one is 0.128. Other statistical moments of the hypsometric curve, i.e. skew (SK), kurtosis (KUR), and the density function (density skew - DSK and density kurtosis-DKUR) show great values, which increased in the south direction of the area study. Accordingly, recent active tectonics (uplift-lower) in the study area is generally weak; however, they are also not completely homogeneous and can be distinguished by different levels. The southwestern side is being lifted higher than the northeastern side. The northern part is being lifted larger than the southern part. In the region, the uplift activities were increased gradually in the Pliocene-Quaternary and could have stopped at certain time in the past. The current geomorphic processes are mainly headward erosion in the upstream.References Allen, C.R., Gillepie, A.R., Han, Y., Sieh, K.E., Zhu, C., 1984. 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The active faults and the maximum earthquakes of the Red River Fault zone in Lao Cai-Yen Bai area, Journal of Sciences of the Earth, Vol. 28, (2), 110-120 (In Vietnamese with English abstract).Ngo Van Liem, Phan Trong Trinh, Nguyen Van Huong, Nguyen Cong Quan, Tran Van Phong, Nguyen Phuc Dat, 2016. Analyze the correlation between the geomorphic indices and recent tectonic active of the Lo River fault zone in southwest of Tam Dao range. Vietnam Journal of Earth Sciences. Vol. 38, No. 1, 1-13 (In Vietnamese with English abstract).Nguyen Quoc Cuong., Zuchiewicz, W., Tokarski. A. K., 1999. Morphotectonic evidence for right-lateral normal slip in the Red River Fault Zone: insights from the study on Tam Dao fault scarp (Viet Nam), J. Geology, Seri B, 13-14, 57-59.Nguyen Xuan Nam, 2015. Quaternary Geology characteristics, present-day tectonic geomorphology of the Da river valley from HoaBinh to Viet Tri and correlation with geological hazards. Doctorate Thesis. 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The University of Science - Vietnam National University, Hanoi (In Vietnamese with English abstract).Wang, P.L., Lo, C.H., Chung, S.L., Lee T.Y., Lan, C.Y., Thang, T.V., 2000. Onset timing of left-lateral movement along the Ailao Shan±Red River Shear Zone: 40Ar/39Ar dating constraint from the Nam Dinh Area, northeastern Vietnam. Journal of Asian Earth Sciences. Volume 18, Issue 3, 1 June 2000, 281-292.Willgoose, G., 1994. A physical explanation for an observed area-slope-elevation relationship for catchments with declining relief. Water Resources Research 30, 151-159.Willgoose, G., Hancock, G., 1998. Revisiting the hypsometric curve as an indicator of form and process in transport-limited catchment. Earth Surface Processes and Landforms 23, 611-623.Zuchiewicz, W., Nguyen Quoc Cuong, Jerzy Zasadni, Nguyen Trong Yem, 2013. Late Cenozoic tectonics of the Red River Fault Zone, Vietnam, in the light of geomorphic studies. Journal of Geodynamics 69, 11-30. 

    ẢNH HƯỞNG CỦA NƯỚC BIỂN DÂNG ĐẾN THỦY TRIỀU KHU VỰC BIỂN MIỀN TRUNG CỦA VIỆT NAM

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    The tide is one of the most important phenomena in the ocean. In the world as well as in Vietnam, the tide was studied very early and great achievements have been recorded. However, under the impact of climate change and sea level rise, the local - to - regional - scale changes will cause significant changes in the coastal system. This paper gives some results of research on the tidal changes in the central region of Vietnam by using the hydrodynamic model and data analysing model. The simulation results of the tide in the central coast of Vietnam show that the tide can change both in the amplitude and phase distribution of the tidal constituents as M2, S2, K1 and O1. Specifically, the results of the average values of M2 are 0.1 m and 10.20; for S2 are 0.12 m and 12.50; for K1 are 0.2 m and 17.20; for O1 are 0.21 m and 20.20. Some results of this study showed that the most important contribution to the change of the tide in the region is the change of topography and the submerged areas.Thủy triều là một trong những hiện tượng quan trọng nhất trong đại dương. Trên thế giới cũng như ở Việt Nam, thủy triều được nghiên cứu từ rất sớm và đã đạt được nhiều thành tựu to lớn. Tuy nhiên, dưới tác động của biến đổi khí hậu và nước biển dâng, các quá trình có quy mô khu vực mang tính chất địa phương sẽ gây ra những thay đổi quan trọng trong các hệ thống ven biển. Bài báo này đưa ra một số kết quả nghiên cứu sự biến đổi của thủy triều trong khu vực biển miền Trung của Việt Nam. Nghiên cứu sử dụng phương pháp mô hình và phân tích điều hòa. Các kết quả mô phỏng về thủy triều trong khu vực biển miền Trung của Việt Nam cho thấy rằng thủy triều có sự biến đổi cả về biên độ và pha của các phân triều chính như M2, S2, K1 và O1. Cụ thể, kết quả giá trị trung bình đối với M2 là 0,1 m và 10,20; đối với S2 là 0,12 m và 12,50; đối với K1 là 0,2 m và 17,20; đối với O1 là 0,21 m và 20,20. Một số kết quả nghiên cứu này đã cho thấy rằng những đóng góp quan trọng nhất vào sự thay đổi của thủy triều trong khu vực là sự thay đổi địa hình và diện tích của thủy vực

    Associations of Psychosocial Factors with Maternal Confidence Among Japanese and Vietnamese Mothers

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    We conducted this cross-sectional study among 392 Japanese and 294 Vietnamese mothers who attended routine child health visits in a Japanese city and at a tertiary hospital in Vietnam, in order to investigate the prevalence and associated sociodemographic, parenting, and psychological characteristics of low maternal confidence in child rearing among them. All data were collected from medical files in Japan, and from medical files and self-administered questionnaires in Vietnam. The proportion of mothers without secure feeling of confidence in the present study was 22% in Japan and 66% in Vietnam. Significant factors associated with a lack of confidence were first-time motherhood and unintended pregnancy in the Japanese dataset and younger age in the Vietnamese dataset. In both groups, a higher proportion of mothers who lacked confidence reported negative parenting outcomes than did confident mothers. Among the three psychological measurements (mood, self-efficacy and depression), higher self-efficacy was associated independently with a significantly reduced risk of not having confidence in child rearing. These results suggest the importance of developing parenting support programs to help Japanese and Vietnamese mothers, particularly those who are young, first-time mothers or who became pregnant unexpectedly, improve their self-efficacy

    Construction of a dataset for the gene nrLSU to support the identification of cantharellus at Langbian Mountain, Lam Dong

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    Fungal species of Cantharellales order are found worldwide including Europe, Africa, Asia, and North America. This clade includes two smaller, separate, but closely related genera Cantharellus and Craterellus. Cantharellus was firstly identified in the middle of the 17th century. Besides traditional classification based on morphology, molecular phylogeny of the nuclear ribosomal large subunit gene (nrLSU) can be an effective tool to provide more information during species identification for this group. In this current report, a dataset of the nrLSU gene including 60 sequences of Cantharellus species and 1 sequence belonging to Craterellus (outgroup), was obtained from Genbank. Phylogenetic analyses by MEGA 6.0 showed a monophyletic relationship between the six well-established clades, namely Cantharellus (Clade 1), Rubrinus (Clade 2), Cinnabarinus (Clade 3), Parvocantharellus (Clade 4), Pseudocantharellus (Clade 5) and subgenus Afrocantharellus (Clade 6) similar to that of morphological classification. Therefore, this dataset is efficient to support the identification of the fungal samples, collected at the Langbian Mountain, Lam Dong

    The Emergence of Rotavirus G12 and the Prevalence of Enteric Viruses in Hospitalized Pediatric Diarrheal Patients in Southern Vietnam

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    Diarrhea is a major cause of childhood morbidity and mortality in developing countries, and the majority of infections are of viral etiology. We aimed to compare the etiological prevalence of the major enteric viruses in an urban and a rural setting in southern Vietnam. We simultaneously screened fecal specimens from 362 children in Ho Chi Minh City and Dong Thap province that were hospitalized with acute diarrhea over a 1-month-long period for four viral gastrointestinal pathogens. Rotavirus was the most common pathogen identified, but there was a differential prevalence of rotavirus and norovirus between the urban and rural locations. Furthermore, rotavirus genotyping and phylogenetic analysis again differentiated the genotypes by the sampling location. Our data show a disproportional distribution of enteric viral pathogens in urban and rural locations, and we provide evidence of continual importation of new rotavirus strains into southern Vietnam and report the emergence of rotavirus genotype G12

    Gem corundum deposits in Vietnam

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    Since 1983, gem-quality rubies have been recovered from the Luc Yen and Quy Chau mining areas in northern Vietnam. Since 1991, 'basaltic'-type blue-green-yellow ('BGY') sapphires have been mined in southern Vietnam. This article briefly reviews the history and geology of these different areas and shows the importance of marble and basalt-type deposits. Other types of corundum occurrences are found in amphibolite, pegmatite, gneiss and metasomatite. The gemmological, chemical and isotopic characteristics of these different types of corundum are described.<br /> The most notable features of rubies contained in marbles are that many crystals have blue colour zones, and inclusions of rutile, anhydrite and salts. The primary fluid inclusions are composed of carbon dioxide and hydrogen sulphide with native sulphur and diaspore daughter minerals. Sapphires from placers in basalts are characterized by inclusions of columbite, pyrochlore and baddeleyite. The trace element contents of corundums allow distinction of rubies in marbles from sapphires in basalts and metamorphic rocks. Rubies have high chromium (0.54<Cr<sub>2</sub>O<sub>3</sub><O.66 wt.%)and low iron (0.01<FeO<0.07 wt.%) contents. The geological origin of Vietnam corundums can be clearly determined from the isotopic composition of their structural oxygen, i.e. δ 18O = 21.0 ± 0.9% for rubies in marbles and δ 18O = 6.6 ± 0.4% for sapphires in basalts

    Multilocus sequence typing of Cryptococcus neoformans var. grubii from Laos in a regional and global context.

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    Cryptococcosis causes approximately 180 000 deaths each year in patients with human immunodeficiency virus (HIV). Patients with other forms of immunosuppression are also at risk, and disease is increasingly recognized in apparently immunocompetent individuals. Cryptococcus neoformans var. grubii, responsible for the majority of cases, is distributed globally. We used the consensus ISHAM Multilocus sequence typing (MLST) scheme to define the population structure of clinical C. neoformans var. grubii isolates from Laos (n = 81), which we placed into the global context using published MLST data from other countries (total N = 1047), including a reanalysis of 136 Vietnamese isolates previously reported. We observed a phylogeographical relationship in which the Laotian population was similar to its neighbor Thailand, being dominated (83%) by Sequence Types (ST) 4 and 6. This phylogeographical structure changed moving eastwards, with Vietnam's population consisting of an admixture of isolates dominated by the ST4/ST6 (35%) and ST5 (48%) lineages. The ST5 lineage is the predominant ST reported from China and East Asia, where it accounts for >90% of isolates. Analysis of genetic distance (Fst) between different populations of C. neoformans var. grubii supports this intermediate structure of the Vietnamese population. The pathogen and host diversity reported from Vietnam provide the strongest epidemiological evidence of the association between ST5 and HIV-uninfected patients. Regional anthropological genetic distances suggest diversity in the C. neoformans var. grubii population across Southeast Asia is driven by ecological rather than human host factors. Where the ST5 lineage is present, disease in HIV-uninfected patients is to be expected
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