Landslide-induced waves are one of the most disastrous hazards that can post a great threat to human lives and properties. At about 4:00 pm, 5 November 2017, a landslide-induced tsunami-like wave ...suddenly occurred across the Truong river in Bac Tra My District, Quang Nam province, Vietnam. The water wave destroyed six houses at the opposite bank and caused one person dead and three others injured. This study seeks to investigate the initiation mechanism and process of the landslide and its impulse wave. First, we examined landslide characteristics through site investigations, unmanned aerial vehicle (UAV) surveys, and laboratory testing with a series of standard geotechnical tests on collected soil samples. Then, the initiation and motion of the rainfall-induced landslides were reproduced by the integrated landslide simulation model (LS-RAPID). Finally, a combined computer simulation of the landslide motion and its impulse wave was performed by using a landslide-induced tsunami simulation model (LS-Tsunami). In which, output data from the LS-RAPID was used as input parameters for LS-Tsunami. The analysis shows that the rainfall with very high intensity in a short-time period was the triggering factor of the landslide, which is common factor in the study area. The 12-, 24-, and 48-h accumulative precipitation prior to the landslide recorded to 530, 760, and 950 mm, respectively. In addition, the rainfall trigger presented a typical pattern of rainstorm events in a long duration. Simulation results show that the impulse wave was generated by the landslide mass rapidly entering the river, crossing the river, and directly causing the disastrous damage to the resident area opposite site of the fail slope. The landslide moved down at a maximum speed of 16.4 m/s when its body approached the water surface and generated a maximum wave height of 5 m. There is good agreement between the observed geomorphic evidences and water traces on the site and simulation results of the landslide and its impulse wave. The paper provides a good case study on the understanding of the mechanism and dynamic process of the whole event that significantly contribute to potential landslide hazard assessment and future disaster mitigation in the area.
We consider the lowest order - so called B-grid - discretization on triangular cells which is common in the ocean or atmosphere simulation science, with pressure field at the vertices of the ...triangles and the velocity field at the cell centers. It is known that this discretization presents spurious modes due to a too large number of velocities unknowns and that these modes should be damped; since preservation of approximate geostrophic equilibrium (GE) may be of primary importance in the simulations, we propose and analyze damping operators that, when applied to the linearized constant coefficient configuration, exactly preserve discrete versions of the GEs. We also analyze their effects in more general configurations and their possible coupling with more standard damping operators. These strategies cover triangular variants of the Low Froude (LF) scheme 1, the Apparent Topography (AT) scheme 2,3, as well as a new modification of it. The LF scheme has no numerical diffusion terms in the pressure equation and damps the normal velocity jumps between adjacent cells in the momentum equation. In the AT scheme, numerical diffusion is added in the pressure equation in such a way that it does not impact the discrete GE. However, since the AT scheme alone cannot be proved to be damping through energy estimates and does not preserve the space which is orthogonal to the discrete GE, we also study what we call the Modified Apparent Topography (MAT) that satisfies these important properties. We also suggest semi-implicit time discretizations that preserve these properties. Extensions to the full non-linear equations are also provided. Numerical experiments illustrate the performance of the new schemes.
•New family of staggered schemes preserving geostrophic equilibria on triangular grids.•The schemes have mimetic properties and are accurate at Low Froude number.•Numerical diffusion ensures stability and damps out spurious modes.•Some of the schemes also preserve orthogonality to geostrophic equilibria.•The associated fully discrete schemes also preserve the above properties.
Introduction
Genetic mutations of PROC and PROS1 are well‐known risk factors for deep venous thrombosis (DVT) in the Asian population. However, the genetic profile of Vietnamese patients with DVT ...remains elusive. This study aimed to investigate the spectrum of genetic mutations of these two genes in Vietnamese patients diagnosed with idiopathic DVT.
Materials and methods
A total of 50 Vietnamese patients diagnosed with idiopathic DVT were recruited in this study. The entire coding regions of the protein C and protein S genes were amplified and directly sequenced to determine genetic alterations.
Results
Four and six genetic mutations were detected in protein C and protein S genes, respectively, in 24 Vietnamese DVT patients. PROC c.565C > T (p.R189W) was the most common mutation found in 13 out of 50 patients, while the mutations of PROS1 comprised three missense and three nonsense variants which diffuse along the gene.
Conclusions
This study shows that mutations of protein C and protein S genes are prevalent in Vietnamese patients diagnosed with idiopathic DVT, and PROC c.565C > T (p.R189W) was the most common genetic alteration.
INTRODUCTION AND IMPORTANCELaparoscopic surgery is recommended to treat recurrent inguinal hernia (IH). Single-incision laparoscopic surgery transabdominal pre-peritoneal (SILS-TAPP) has been an ...option for IH repair but few studies on the application of this method for recurrent IH was conducted. We aimed to report our experience of SILS-TAPP for recurrent IH and the long-term outcomes of this technique.CASE PRESENTATIONTen patients of recurrent IH, including three multiple recurrences, were successfully treated with SILS-TAPP. Previous surgeries were Bassini and Lichtenstein's procedures. No perioperative complications were observed; neither additional trocar nor conversion to open surgery was needed. Median operation time was 65 (range: 45-95) minutes. Post-operative pain lasted for two to three days. Neither long-term complications nor recurrence was seen until the median follow-up time of 37 (range: 16-53) months.CLINICAL DISCUSSIONAlthough the surgical procedure of hernia repair of SILS-TAPP was the same as conventional TAPP, the manipulation of the instrument was technically challenging. This surgical method should be done by an SILS expert with application of several surgical tips to overcome difficulties adhering to single-port surgery. Also, meticulous and patient dissection of the inguinal site is suggested.CONCLUSIONSILS-TAPP is safe and feasible to repair recurrent inguinal hernia. However, it should be done by experienced surgeons.
•Properties of red mud in Vietnam's Tan Rai Alumina plant.•Dissolution ratio of SiO2 and Al2O3 in red mud, fly ash under different conditions.•Properties of red mud based alkali activated material ...after high temperature and autoclave curing.•Regression between the compressive strength and the total amount of dissolved SiO2.
To produce the alkali activated material, red mud must be used with components containing active silicon dioxide because silicon dioxide in red mud does not dissolve in alkaline solution. The test results presented in this paper show that high pressure and high temperature treatment in an autoclave can dissolve part of the silicone dioxide in red mud and improve the properties of material. The compressive strength of red mud based alkali activated materials can reach 10.6 MPa with a softening coefficient over 0.70. Adding an active silicon dioxide supplement by replacing 26.3 wt% red mud with fly ash increases the compressive strength up to 20 MPa and the softening coefficient by more than 0.90. Furthermore, autoclave treatment reduces residual sodium hydroxide and lowers the pH value of material. As the result, red mud based and red mud-fly ash based alkali activated materials can be used for manufacturing of masonry units.
There are increasing concerns regarding the role of exposure to ambient air pollution during pregnancy in the development of early childhood cancers.
This population based study examined whether ...prenatal and early life (<1year of age) exposures to ambient air pollutants, including nitrogen dioxide (NO2) and particulate matter with aerodynamic diameters ≤2.5μm (PM2.5), were associated with selected common early childhood cancers in Canada.
2,350,898 singleton live births occurring between 1988 and 2012 were identified in the province of Ontario, Canada. We assigned temporally varying satellite-derived estimates of PM2.5 and land-use regression model estimates of NO2 to maternal residences during pregnancy. Incident cases of 13 subtypes of pediatric cancers among children up to age 6 until 2013 were ascertained through administrative health data linkages. Associations of trimester-specific, overall pregnancy and first year of life exposures were evaluated using Cox proportional hazards models, adjusting for potential confounders.
A total of 2044 childhood cancers were identified. Exposure to PM2.5, per interquartile range increase, over the entire pregnancy, and during the first trimester was associated with an increased risk of astrocytoma (hazard ratio (HR) per 3.9μg/m3=1.38 (95% CI: 1.01, 1.88) and, HR per 4.0μg/m3=1.40 (95% CI: 1.05–1.86), respectively). We also found a positive association between first trimester NO2 and acute lymphoblastic leukemia (ALL) (HR=1.20 (95% CI: 1.02–1.41) per IQR (13.3ppb)).
In this population-based study in the largest province of Canada, results suggest an association between exposure to ambient air pollution during pregnancy, especially in the first trimester and an increased risk of astrocytoma and ALL. Further studies are required to replicate the findings of this study with adjustment for important individual-level confounders.
•Ambient air pollution in pregnancy increases the risk of childhood cancers.•PM2.5 exposure in first trimester was associated with risk of astrocytoma.•First trimester exposure to NO2 increased risk of acute lymphoblastic leukemia.
Vaginal candidiasis is frequent in women of reproductive age. Accurate identification Candida provides helpful information for successful therapy and epidemiology study; however, there are very ...limited data from the Vietnam have been reported. This study was performed to determine the prevalence, species distribution of yeast causing vaginal discharge and antifungal susceptibility patterns of Candida albicans among symptomatic non-pregnant women of reproductive age. Vaginal discharge samples were collected from 462 women of reproductive age in Hanoi, Vietnam between Sep 2019 and Oct 2020. Vaginal swabs from these patients were examined by direct microscopic examination (10% KOH). CHROMagarTM Candida medium and Sabouraud dextrose agar supplemented with chloramphenicol (0.5 g/l) were used to isolate yeast, and species identification was performed using morphological tests and molecular tools (PCR and sequencing). Antifungal susceptibility testing was determined according to the Clinical and Laboratory Standards Institute guidelines (M27-A3 and M27-S4). The prevalence of vaginal yeast colonization in non-pregnant women was 51.3% of 462 participants. Nine different yeast species were identified. Among these isolates, C. albicans (51.37%) was the most frequent, followed by C. parapsilosis (25.88%), C. glabrata (11.37%), C. tropicalis (4.31%), C. krusei (3.92%), C. africana (1.57%), Saccharomyces cerevisiae (0.78%), C. nivariensis (1 isolates, 0.39%), and C. lusitaniae (1 isolates, 0.39%), respectively. Among C. albicans, all 46 isolates were 100% susceptible to micafungin, caspofungin, and miconazole. The susceptibility rates to amphotericine B, 5-flucytosine, fluconazole, itraconazole and voriconazole were 95.65, 91.30, 91.30, 82.61 and 86.95%, respectively. The prevalence of VVC among symptomatic non-pregnant women of reproductive age in Vietnam was higher than many parts of the world. The high frequency of non-albicans Candida species, which were often more resistant to antifungal agents, was a notable feature. Resistance rates of vaginal C. albicans isolates to antifungal agents was low. Our findings suggest that continued surveillance of changes in species distribution and susceptibility to antifungals should be routinely screened and treated.
An estimated 91,998,400 L of herbicides were stocked at three US airbases in Vietnam between 1962 and 1971. These herbicides were contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin ...(2,3,7,8-tetraCDD). In 2017, we sampled blood from 120 male Vietnamese military workers in the three dioxin-contaminated airbases (Bien Hoa, Da Nang, and Phu Cat) and from 20 workers at an uncontaminated airbase. 2,3,7,8-tetraCDD concentrations were highest in samples from Bien Hoa (18.2 pg/g lipid), followed by samples from Da Nang (9.2 pg/g lipid), Phu Cat (3.7 pg/g lipid), and the reference base (2.1 pg/g lipid). In Bien Hoa, 31 of the 50 subjects had blood 2,3,7,8-tetraCDD levels in the range of 10–100 pg/g lipid and four subjects had 2,3,7,8-tetraCDD levels that exceeded 100 pg/g lipid. In Da Nang, almost half of the subjects had blood 2,3,7,8-tetraCDD concentrations in the range of 10–100 pg/g lipid. These findings suggest that military workers at contaminated bases are the population most vulnerable to dioxin exposure, especially at Bien Hoa.
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•Dioxin originated from Agent Orange spraying in Vietnam War is a serious public concern.•Military workers at dioxin-contaminated airbases are the population most vulnerable to dioxin exposure.•2,3,7,8-tetraCDD concentrations in blood samples were highest in Bien Hoa airbase (18.2 pg/g lipid), followed by samples from Da Nang (9.2 pg/g lipid), and Phu Cat (3.7 pg/g lipid).•Remediation of dioxin-contaminated airbases is necessary for public health protection of populations living inside and around the airbases.
The coronavirus disease 2019 (COVID-19) pandemic will have a large impact on the publishing industry. This research aims to investigate the influences of the COVID-19 pandemic situation, utilitarian ...and hedonic motivations on consumer intention to buy books online. It conceptualizes the effects of the COVID-19 pandemic as situational influences, which involve the closure of physical bookstores, health risks associated with visiting such stores, online shopping trend and additional marketing efforts from online bookstores during the pandemic. Data were collected from 275 Vietnamese consumers using an online survey. Multivariate data analysis reveals that the COVID-19 pandemic situation has a positive and significant impact on consumer intention toward online book shopping. Furthermore, while utilitarian motivation exerts a strong effect on consumer intention to purchase books online, the relationship between hedonic motivation and online purchase intention is positive but insignificant. These findings would assist key stakeholders such as publishers and online bookstores to improve the quality of their websites as well as develop their marketing campaigns.
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