| 1. |
- Tran, Quoc Cuong, et al.
(författare)
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Novel Ensemble Landslide Predictive Models Based on the Hyperpipes Algorithm : A Case Study in the Nam Dam Commune, Vietnam
- 2020
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Ingår i: Applied Sciences. - Switzerland : MDPI. - 2076-3417. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- Development of landslide predictive models with strong prediction power has become a major focus of many researchers. This study describes the first application of the Hyperpipes (HP) algorithm for the development of the five novel ensemble models that combine the HP algorithm and the AdaBoost (AB), Bagging (B), Dagging, Decorate, and Real AdaBoost (RAB) ensemble techniques for mapping the spatial variability of landslide susceptibility in the Nam Dan commune, Ha Giang province, Vietnam. Information on 76 historical landslides and ten geo-environmental factors (slope degree, slope aspect, elevation, topographic wetness index, curvature, weathering crust, geology, river density, fault density, and distance from roads) were used for the construction of the training and validation datasets that are the prerequisites for building and testing the proposed models. Using different performance metrics (i.e., the area under the receiver operating characteristic curve (AUC), negative predictive value, positive predictive value, accuracy, sensitivity, specificity, root mean square error, and Kappa), we verified the proficiency of all five ensemble learning techniques in increasing the fitness and predictive powers of the base HP model. Based on the AUC values derived from the models, the ensemble ABHP model that yielded an AUC value of 0.922 was identified as the most efficient model for mapping the landslide susceptibility in the Nam Dan commune, followed by RABHP (AUC = 0.919), BHP (AUC = 0.909), Dagging-HP (AUC = 0.897), Decorate-HP (AUC = 0.865), and the single HP model (AUC = 0.856), respectively. The novel ensemble models proposed for the Nam Dan commune and the resultant susceptibility maps can aid land-use planners in the development of efficient mitigation strategies in response to destructive landslides.
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| 2. |
- Giang, Kim Bao, et al.
(författare)
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Relative Importance of Different Attributes of Graphic Health Warnings on Tobacco Packages in Viet Nam
- 2016
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Ingår i: Asian Pacific Journal of Cancer Prevention. - 1513-7368. ; 17, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- Graphic health warnings (GHW) on tobacco packages have proven to be effective in increasing quit attempts among smokers and reducing initial smoking among adolescents. This research aimed to examine the relative importance of different attributes of graphic health warnings on tobacco packages in Viet Nam. A discrete choice experimental (DCE) design was applied with a conditional logit model. In addition, a ranking method was used to list from the least to the most dreadful GHW labels. With the results from DCE model, graphic type was shown to be the most important attribute, followed by cost and coverage area of GHW. The least important attribute was position of the GHW. Among 5 graphic types (internal lung cancer image, external damaged teeth, abstract image, human suffering image and text), the image of lung cancer was found to have the strongest influence on both smokers and non-smokers. With ranking method, the image of throat cancer and heart diseases were considered the most dreadful images. GHWs should be designed with these attributes in mind, to maximise influence on purchase among both smokers and non-smokers.
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| 3. |
- Hoang-Minh, Thao, et al.
(författare)
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Use of TEM-EDX for structural formula identification of clay minerals : a case study of Di Linh bentonite, Vietnam
- 2019
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Ingår i: Journal of applied crystallography. - : International Union of Crystallography (IUCr). - 0021-8898 .- 1600-5767. ; 52:1, s. 133-147
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Tidskriftsartikel (refereegranskat)abstract
- Transmission electron microscopy linked with energy-dispersive X-ray spectroscopy (TEM-EDX) was applied to characterize mineralogical signals ofweathering processes in the Di Linh bentonite deposit (Vietnam) and to visualize the effects of Na activation on the smectitic phases. Modelling of X ray diffraction patterns (oriented mount) was applied in order to refine the computed structural formula. X-ray diffraction, X-ray fluorescence and Fouriertransform infrared spectroscopy (FT-IR) methods were also applied to verify the TEM-EDX results. An Excel-based routine has been developed in this research to allow fast computation of structural formulae and classification of the investigated clay particles. This routine supports the acquirement of 100 300 TEM-EDX analyses as a representative set of individual particles for each sample. The Excel-based routine involves end members of different clay mineral groups and interstratifications with two or three members (e.g. illite smectite interstratifications – IS-ml; dioctahedral vermiculite–smectite interstratifications – diVS-ml; and kaolinite–montmorillonite–dioctahedral vermiculite interstratifications – KSV-ml). The routine is now freely available. According to the identification procedure, the <2 mm fraction of the Di Linh bentonite (Vietnam) is composed mainly of K- and charge-deficient illite smectite interstratifications (or diVS-ml): montmorillonite-rich randomly ordered (R0) type and illite-rich regularly ordered (R1) type. Additionally, Fe-poor KSV-ml was identified.Industrial Na activation of the Di Linh bentonite resulted in an increase of theR1 diVS-ml portion and dissolution of a large part of the smectite-rich phases.The TEM-EDX approach also gave analytical proof of a sedimentary processfor Di Linh smectite. The parent muscovite was altered in two different environments: (i) K-leaching and layer-wise alteration into kaolinite (weathering), and (ii) further edge-controlled alteration of mica into lath-like montmorillonite particles associated with a dissolution of kaolinite layers from the former kaolinite–mica intergrowths by heat impact (basalt flow).
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| 4. |
- Minh, Hoang Van, et al.
(författare)
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Tobacco Control Policies in Vietnam : Review on MPOWER Implementation Progress and Challenges
- 2016
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Ingår i: Asian Pacific Journal of Cancer Prevention. - 1513-7368. ; 17, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- In Vietnam, the WHO Framework Convention on Tobacco Control (WHO FCTC) took effect in March 2005 while MPOWER has been implemented since 2008. This paper describes the progress and challenges of implementation of the MPOWER package in Vietnam. We can report that, in term of monitoring, Vietnam is very active in the Global Tobacco Surveillance System, completing two rounds of the Global Adult Tobacco Survey (GATS) and three rounds of the Global Youth Tobacco Survey (GYTS). To protect people from tobacco smoke, Vietnam has issued and enforced a law requiring comprehensive smoking bans at workplaces and public places since 2013. Tobacco advertising and promotion are also prohibited with the exception of points of sale displays of tobacco products. Violations come in the form of promotion girls, corporate social responsibility activities from tobacco manufacturers and packages displayed by retail vendors. Vietnam is one of the 77 countries that require pictorial health warnings to be printed on cigarette packages to warn about the danger of tobacco and the warnings have been implemented effectively. Cigarette tax is 70% of factory price which is equal to less than 45% of retail price and much lower than the recommendation of WHO. However, Vietnam is one of the very few countries that require manufacturers and importers to make "compulsory contributions" at 1-2% of the factory price of cigarettes sold in Vietnam for the establishment of a Tobacco Control Fund (TCF). The TCF is being operated well. In 2015, 67 units of 63 provinces/cities, 22 ministries and political-social organizations and 6 hospitals received funding from TCF to implement a wide range of tobacco control activities. Cessation services have been starting with a a toll-free quit-line but need to be further strengthened. In conclusion, Vietnam has constantly put efforts into the tobacco control field with high commitment from the government, scientists and activists. Though several remarkable achievements have been gained, many challenges remain. To overcome those challenges, implementation strategies that take into account the contextual factors and social determinants of tobacco use in Vietnam are needed.
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| 5. |
- Bett, Bernard, et al.
(författare)
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Spatiotemporal analysis of historical records (2001-2012) on dengue fever in Vietnam and development of a statistical model for forecasting risk
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dengue fever is the most widespread infectious disease of humans transmitted by Aedes mosquitoes. It is the leading cause of hospitalization and death in children in the Southeast Asia and western Pacific regions. We analyzed surveillance records from health centers in Vietnam collected between 2001-2012 to determine seasonal trends, develop risk maps and an incidence forecasting model.METHODS: The data were analyzed using a hierarchical spatial Bayesian model that approximates its posterior parameter distributions using the integrated Laplace approximation algorithm (INLA). Meteorological, altitude and land cover (LC) data were used as predictors. The data were grouped by province (n = 63) and month (n = 144) and divided into training (2001-2009) and validation (2010-2012) sets. Thirteen meteorological variables, 7 land cover data and altitude were considered as predictors. Only significant predictors were kept in the final multivariable model. Eleven dummy variables representing month were also fitted to account for seasonal effects. Spatial and temporal effects were accounted for using Besag-York-Mollie (BYM) and autoregressive (1) models. Their levels of significance were analyzed using deviance information criterion (DIC). The model was validated based on the Theil's coefficient which compared predicted and observed incidence estimated using the validation data. Dengue incidence predictions for 2010-2012 were also used to generate risk maps.RESULTS: The mean monthly dengue incidence during the period was 6.94 cases (SD 14.49) per 100,000 people. Analyses on the temporal trends of the disease showed regular seasonal epidemics that were interrupted every 3 years (specifically in July 2004, July 2007 and September 2010) by major fluctuations in incidence. Monthly mean minimum temperature, rainfall, area under urban settlement/build-up areas and altitude were significant in the final model. Minimum temperature and rainfall had non-linear effects and lagging them by two months provided a better fitting model compared to using unlagged variables. Forecasts for the validation period closely mirrored the observed data and accurately captured the troughs and peaks of dengue incidence trajectories. A favorable Theil's coefficient of inequality of 0.22 was generated.CONCLUSIONS: The study identified temperature, rainfall, altitude and area under urban settlement as being significant predictors of dengue incidence. The statistical model fitted the data well based on Theil's coefficient of inequality, and risk maps generated from its predictions identified most of the high-risk provinces throughout the country.
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| 6. |
- Bui, Ha Thi Thu, et al.
(författare)
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The Association Between Gender Inequalities and Women's Utilization of Maternal Health Services : A Cross-Sectional Survey in Eight South Central Coast Provinces, Vietnam
- 2018
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Ingår i: Journal of Public Health Management and Practice. - 1078-4659 .- 1550-5022. ; 24:2, s. S19-S27
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Tidskriftsartikel (refereegranskat)abstract
- Background: Gender inequalities influence the utilization of maternal health services in Vietnam, but little research has been published. This study, therefore, aimed to explore the association between gender inequalities and women's utilization of maternal health services in Vietnam.Methods: The study was conducted in 8 provinces in the South Central Coast region of Vietnam during August 2013 to May 2014. A total of 907 women who delivered a year prior to the date of interview participated in the study. A multiple logistic regression model was used to examine the association between gender inequalities (including sociodemographic determinants of health) and utilization of 4 or more antenatal care (ANC4+) services, institutional delivery, and ever used contraceptive methods.Results: The utilization rate of maternal health services was varied, from 53.9% for ANC4+ to 87.7% for ever used a contraceptive method and 97% for institutional delivery. Ethnicity was identified as the most influential variable out of all sociodemographic determinants of health. Regarding gender inequalities, couple communication was the only variable having significant association with women's utilization of maternal health services.Conclusion: Women's equal role within context of their daily life and relations with their husbands (discussing maternal care with husband and having equal income to husband) supported their use of maternal health services. Therefore, there should be concerted efforts from all relevant stakeholders including the health system to focus on disadvantaged women in planning and delivery of maternal health services, especially to ethnic minority women. Male involvement strategy should be implemented to promote maternal health care, especially during the prenatal and postpartum period. To provide more culturally sensitive and right-based approaches in delivery of maternal health services to disadvantaged women in Vietnam, interventions are recommended that promote male involvement, that is, to engage men in service delivery to adapt and ensure the most appropriate and effective maternal health care.
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| 7. |
- Chuong, Nguyen Canh, et al.
(författare)
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Amniocentesis test uptake for congenital defects : Decision of pregnant women in Vietnam
- 2018
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Ingår i: Health Care for Women International. - : TAYLOR & FRANCIS INC. - 0739-9332 .- 1096-4665. ; 39:4, s. 493-504
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Tidskriftsartikel (refereegranskat)abstract
- Our study aimed to identify the knowledge, attitude, and factors associated with uptake of amniocentesis test amongst pregnant women of advanced maternal age (35+ years old). A cross-sectional survey was performed on 481 participants in 2016. Women with higher educational attainment, higher income level, having a baby with congenital defects, and women with better knowledge and/or attitude about amniocentesis test were more likely to accept the test. Our study suggested the importance of counseling for women and more time should be given for them to absorb information before they make their decision to uptake the amniocentesis test.
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| 8. |
- Duc, Duong M., 1984-, et al.
(författare)
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A Secular Trend in Birth Weight and Delivery Practices in Periurban Vietnam During 2005-2012
- 2017
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Ingår i: Asia-Pacific journal of public health. - : SAGE PUBLICATIONS INC. - 1010-5395 .- 1941-2479. ; 29:5 Suppl., s. 18S-24S
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Tidskriftsartikel (refereegranskat)abstract
- The remarkable increase in Vietnamese economic conditions can increase the birth weight in neonates and better delivery practices among women. The Chi Linh Health and Demographic Surveillance System started in 2004. An open cohort of data consisting of about 57561 people from 17993 households has been followed primarily with respect to demography, economy, and education. The aim of this research is to study secular trends in delivery practice and birth weight in the past decade (2005-2012) in Chi Linh. We found a significant change in delivery rates at hospitals and cesarean section rates, but the birth weights over a decade of drastic economic development were stable. Furthermore, the findings show significant associations of birth weight and delivery practices with the child's sex, mother's age, and household income. Our results might be considered as representative for other similar periurban settings in Vietnam. We suggest that appropriate policies should be developed given the reduction in the use of delivery services in commune health centers in urban areas.
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| 9. |
- Le, Vui Thi, et al.
(författare)
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Sex Ratio at Birth in Vietnam : Results From Data in CHILILAB HDSS, 2004 to 2013
- 2017
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Ingår i: Asia-Pacific journal of public health. - : SAGE PUBLICATIONS INC. - 1010-5395 .- 1941-2479. ; 29:5 Suppl., s. 25S-34S
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to explore the association of demographic and socioeconomic characteristics and imbalanced sex ratio at birth (SRB) in Chi Linh district, Hai Duong. The data were collected from a longitudinal study using a community-based periodic, referred as Chi Linh Health and Demographic Surveillance System (CHILILAB HDSS) during 2004 to 2013. A total of 7568 children were analyzed. Results showed that SRB in Chi Linh dramatically increased to the imbalanced sex ratio (114.6 boys to 100 girls) by 2013. SRB was associated with birth order and sex of preceding siblings. SRB was extremely high among families without any sons (136/100). SRB was highest among families having third or more children (175/100). Imbalanced SRB was more likely to occur among women working in small business/homemakers and others, women who attained high education level, and women in wealthy households. We suggested further efforts to tackle imbalanced SRB in periurban areas in Vietnam.
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| 10. |
- Nguyen, Anh Mai, et al.
(författare)
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Sizeable Macroporous Monolithic Polyamide Entities Prepared in Closed Molds by Thermally Mediated Dissolution and Phase Segregation
- 2008
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 20:19, s. 6244-6247
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Tidskriftsartikel (refereegranskat)abstract
- A simple method is presented for the preparation of macroporous monoliths from an aliphatic polyamide in closed molds, based on swelling/dissolution in benzyl alcohol at elevated temperature, followed by precipitation into a continuous monolithic structure by cooling the solution below the upper critical solution temperature. Subsequent removal of the solvent led to the formation of rigid macroporous nylon monoliths with a continuous and evenly spaced macropore system. The intended use is as supports for flow-through systems, where efficient mass transport at low flow resistance is the key optimization criterion.
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