103 research outputs found
Analytically weak solutions to SPDEs with unbounded time-dependent differential operators and an application
We analyze the concepts of analytically weak solutions of stochastic
differential equations (SDEs) in Hilbert spaces with time-dependent unbounded
operators and give conditions for existence and uniqueness of such solutions.
Our studies are motivated by a stochastic partial differential equation (SPDE)
arising in industrial mathematics
NGHIÊN CỨU ĐÁNH GIÁ TRƯỢT ĐẤT KHU VỰC THỪA THIÊN - HUẾ
Studying landslide hazards in Thuathien - Hue is based on the relationship between landslide and its controlling factors (topographical slope, rainfall, landuse, weathering crust, lithological properties, fault and road proximity), evaluated in a key areas. This relationship is quantified by weighting the classes in each factor and weighting each factor in a set of landslide-controlling factors. This is the bases for landslide susceptibility mapping given by integrating the weighted factor maps. The class is weighted by its landslide density, normalized on a 1-to-9 scale. The factor weighting is determined based on the landslide quantity, which would be engendered in a whole province with considering thelandslide density in each class as that obtained from the key area. The calculated results show that, influences of landslide-controlling factors in Thuathien - Hue may increase in following order: road proximity, landuse, weathering, fault, lithology, rainfall, and slope. The areas of very low, low, medium, high and very high landslide hazards accountrespectively 12,36%, 15,34%, 39,69%, 31,89% and 0,82% of province. The high and very hazards are distributed in linear form, suggesting a strong influence of faults in these areas.ReferencesAyalew L., Yamagishi H. and Ugawa N., 2004. Landslide susceptibility mapping using GIS in Tsugawa area of Agano River, Niigata Prefecture, Japan. Landslides, 1, 73-81.Ayalew L., and Yamagishi H., 2005. The application of GIS-based logistic regression for landslide susceptibility mapping in the Kakuda - Yahiko Mountains, Centrall Japan. Geomorphology 65. 15-31.Guzzetti F., Carrara A., Cardinali M. and Reichenbach P., 1999. Landslide hazard evaluation : a review of current techniques and their application in a multi-scale study, Central Italy. Geomorphology 31, 181-216.Phạm Văn Hùng, Nguyễn Xuân Huyên, 2010. Đánh giá hiện trạng và phân vùng cảnh báo nguy cơ trượt lở đất thành phố Đà Nẵng. Tạp chí Các KH về TĐ, T.32, (2), 106-113.Phạm Văn Hùng, 2011. Đánh giá hiện trạng và phân vùng cảnh báo nguy cơ trượt lở đất tỉnh Quảng Nam. Tạp chí Các KH về TĐ, T.33, 3ĐB, 518-525.Pachauri AK, Gupta PV, Chander R, 1998. Landslide zoning in a part of the Garhwal Himalayas. Environ. Geol. 36 (3-4), 325-334.Saaty Thomas, 1994. Fundamental of decision making and priority theory with analytic hierarchy process. Pittsburgh: RWS publication, 527p.Schuster R.L., 1996. Socioeconomic significance of landslides. In Landslides: investigation and mitigation, ed. A.K. Turner, R.L. Schuster, p. 12-35. Washington: National Academy Press.Shaban A., Khawlie M., Bou Kheir R., Abdallah C., 2001. Assessment of road instability along a typical moutainous road using GIS and aerial photos, Lebanon, Eastern Mediterranean. Bulletin of Engineering Geology and Environment 60, 93-101.Studying landslide hazards in Thuathien - Hue is based on the relationship between landslide and its controllingfactors (topographical slope, rainfall, landuse, weathering crust, lithological properties, fault and road proximity),evaluated in a key areas. This relationship is quantified by weighting the classes in each factor and weighting each factorin a set of landslide-controlling factors. This is the bases for landslide susceptibility mapping given by integrating theweighted factor maps. The class is weighted by its landslide density, normalized on a 1-to-9 scale. The factor weightingis determined based on the landslide quantity, which would be engendered in a whole province with considering thelandslide density in each class as that obtained from the key area. The calculated results show that, influences oflandslide-controlling factors in Thuathien - Hue may increase in following order: road proximity, landuse, weathering,fault, lithology, rainfall, and slope. The areas of very low, low, medium, high and very high landslide hazards accountrespectively 12,36%, 15,34%, 39,69%, 31,89% and 0,82% of province. The high and very hazards are distributed inlinear form, suggesting a strong influence of faults in these areas
NOWJ1@ALQAC 2023: Enhancing Legal Task Performance with Classic Statistical Models and Pre-trained Language Models
This paper describes the NOWJ1 Team's approach for the Automated Legal
Question Answering Competition (ALQAC) 2023, which focuses on enhancing legal
task performance by integrating classical statistical models and Pre-trained
Language Models (PLMs). For the document retrieval task, we implement a
pre-processing step to overcome input limitations and apply learning-to-rank
methods to consolidate features from various models. The question-answering
task is split into two sub-tasks: sentence classification and answer
extraction. We incorporate state-of-the-art models to develop distinct systems
for each sub-task, utilizing both classic statistical models and pre-trained
Language Models. Experimental results demonstrate the promising potential of
our proposed methodology in the competition.Comment: ISAILD@KSE 202
Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021
We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions
Chemical profiles and biological activities of acetone extracts of nine Annonaceae plants
This study investigated the chemical components and bioactivities of acetone leaf extracts of nine Annonaceae plants collected in the Binh Chau-Phuoc Buu Nature Reserve, Vietnam. A total of 182 constituents were identified, with linolenic acid, diaeudesmin, germacrene D, 1-octadecenoic acid, 8-(3-octyl-2-oxiranyl)-1-octanol, oleic acid, and phenylmethyl ester being the major compounds. The antimicrobial activity of the extracts was evaluated using a disc diffusion assay. Eight of the nine extracts, except for the Mitrephora thorelii extract, showed an inhibition effect against Bacillus cereus and Staphylococcus aureus. The antioxidant activity of the extracts was determined using DPPH assay, and the cytotoxic activity was deter mined using SRB assay. The results showed that the acetone extracts of Artabotrys hexapetalus, Uvularia grandiflora, Polyalthia luensis, Xylopia pierrei, Sphaerocoryne affinis, Desmos cochinchinensis, Uvaria littoralis, Mitrephora thorelii, and Goniothalamus touranensis had significant activity with IC50 for the DPPH radical scavenging activity ranging from 18.56 to 702.33 μg/mL, and the IC50 for the cytotoxic effects ranged from 5.39 to 251.77 μg/mL. Overall, the results obtained provide experimental evidence for the potential use of these plants in medicine and other related fields
EVALUATION OF GENETIC DIVERSITY OF THE BLACK GLUTINOUS RICE BASED ON AGRO-MORPHOLOGICAL CHARACTERS
The study assessed the variations in nine agro-morphological characters among and within the black glutinous rice (Oryza sativa) population from Chau Thanh District, Tra Vinh Province. The nine quantitative agromorphological characters that were measured include culm length, leaf length, leaf width, number of panicles, panicle length, grain length, grain width, number of firm grain, and number of grain per panicle. The unweighted pair group method with arithmetic mean method and principal coordinate analysis by the NTSYS program were applied in this study to classify the nine agro-morphological characters. In addition, to
compare the variations in quantitative characters between O. sativa populations, one-way analysis of variance (ANOVA) was used. The results showed significant differences between the black glutinous rice populations for all quantitative agro-morphological characters. Moreover, some agro-morphological characters showed positive correlations to each other. The dendrogram generated from the analysis process of the agromorphological data divided the O. sativa populations into two groups with unfamiliar features. However, the O. sativa populations assessed exhibited a wide range of variations in morphological characteristics, both within the same population and among other populations with the same strains
CSA: Thực hành nông nghiệp thông minh với khí hậu ở Việt Nam
During the last five years, Vietnam has been one of the countries most affected by climate change. Severe typhoons, flooding, cold spells, salinity intrusion, and drought have affected agriculture production across the country, from upland to lowland regions. Fortunately for Vietnam, continuous work in developing climate-smart agriculture has been occurring in research organizations and among innovative farmers and entrepreneurs. Application of various CSA practices and technologies to adapt to the impact of climate change in agriculture production have been expanding. However, there is a need to accelerate the scaling process of these practices and technologies in order to ensure growth of agriculture production and food security, increase income of farmers, make farming climate resilient, and contribute to global climate change mitigation. This book aims to provide basic information to researchers, managers, and technicians and extentionists at different levels on what CSA practices and technologies can be up scaled in different locations in Vietnam
Differential prevalence and geographic distribution of hepatitis C virus genotypes in acute and chronic hepatitis C patients in Vietnam.
BACKGROUND: The highest burden of disease from hepatitis C virus (HCV) is found in Southeast Asia, but our understanding of the epidemiology of infection in many heavily burdened countries is still limited. In particular, there is relatively little data on acute HCV infection, the outcome of which can be influenced by both viral and host genetics which differ within the region. We studied HCV genotype and IL28B gene polymorphism in a cohort of acute HCV-infected patients in Southern Vietnam alongside two other cohorts of chronic HCV-infected patients to better understand the epidemiology of HCV infection locally and inform the development of programs for therapy with the increasing availability of directly acting antiviral therapy (DAAs). METHODS: We analysed plasma samples from patients with acute and chronic HCV infection, including chronic HCV mono-infection and chronic Human Immunodeficiency Virus (HIV)-HCV coinfection, who enrolled in four epidemiological or clinical research studies. HCV infection was confirmed with RNA testing. The 5' UTR, core and NSB5 regions of HCV RNA positive samples were sequenced, and the genotype and subtype of the viral strains were determined. Host DNA from all HCV positive patients and age- and sex-matched non-HCV-infected control individuals were analysed for IL28B single nucleotide polymorphism (SNP) (rs12979860 and rs8099917). Geolocation of the patients were mapped using QGIS. RESULTS: 355 HCV antibody positive patients were analysed; 54.6% (194/355) and 46.4% (161/355) were acute and chronic infections, respectively. 50.4% (81/161) and 49.6.4% (80/161) of chronic infections had HCV mono-infection and HIV-HCV coinfection, respectively. 88.7% (315/355) and 10.1% (36/355) of the patients were from southern and central regions of Vietnam, respectively. 92.4% (328/355) of patients were HCV RNA positive, including 86.1% (167/194) acute and 100% (161/161) chronic infections. Genotype could be determined in 98.4% (322/328) patients. Genotypes 1 (56.5%; 182/322) and 6 (33.9%; 109/322) predominated. Genotype 1 including genotype 1a was significantly higher in HIV-HCV coinfected patients compared to acute HCV patients [43.8% (35/80) versus 20.5% (33/167)], (p = <0.001), while genotype 6 was significantly higher in chronic HCV mono-infected patients [(44.4% (36/81) versus 20.0% (16/80)] (p = < 0.004) compared to HIV-HCV coinfected patients. The prevalence of IL28B SNP (rs12979860) homozygous CC was 86.46% (83/96) in control individuals and was significantly higher in acutely-infected compared to chronically-infected patients [93.2 (82/88) versus 76.1% (35/46)] (p = < 0.005). CONCLUSION: HCV genotype 6 is highly prevalent in Vietnam and the high prevalence in treatment naïve chronic HCV patients may results from poor spontaneous clearance of acute HCV infection with genotype 6
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