| 1. |
- Shao, Wei, et al.
(författare)
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Reduce uncertainty in soil hydrological modeling : A comparison of soil hydraulic parameters generated by random sampling and pedotransfer function
- 2023
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Ingår i: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 623
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Tidskriftsartikel (refereegranskat)abstract
- Numerical simulation of unsaturated soil hydrology relies on calibrated soil hydraulic parameters, which are subject to uncertainty due to imperfect information during the inverse modelling. This study investigates the effectiveness of reducing parameter uncertainty using the recently developed Rosetta 3 pedotransfer function. The GLUE method was employed for numerical modeling using the Darcy-Richards equation under two strategies for sampling Mualem-van Genuchten (MvG) parameters: the first uses conventional random generation of MvG parameters (GLUE-random), while the second adopts Rosetta 3 to transfer soil particle composition to MvG parameter (GLUE-Rosetta). Both approaches were used for inverse modeling of 9 typical soils, each with a recommended parameter set defined as true values and associated soil moisture dynamics as observations. The posterior parameters selected with both GLUE-random and GLUE-Rosetta show an equifinality phenomenon. GLUE-random fails to provide well-constrained posterior parameters to recover the pre-defined true values, and its posterior results of soil water characteristic curve (SWCC) and soil hydraulic conductivity function (HCF) are poorly constrained. In contrast, GLUE-Rosetta significantly improves the accuracy of the inversely-estimated soil hydraulic parameters, and the ensemble of posterior SWCC and HCF also encompasses the predefined true curves. The results demonstrate the effectiveness of using Rosetta 3 to reduce the dimensionality of the optimization problem, which results in reliable estimation of soil hydraulic parameters and soil particle compositions. Moreover, GLUE-Rosetta outperforms GLUE-random in predicting soil moisture dynamics under different rainfall intensities. Overall, it is recommended to integrate Rosetta 3 with existing optimization tools to reduce the uncertainty of soil parameters and support more reliable modeling of unsaturated soil hydrology.
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| 2. |
- Shao, Wei, et al.
(författare)
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Reducing uncertainties in hydromechanical modeling with a recently developed Rosetta 3 podeotransfer function
- 2023
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Ingår i: Engineering Geology. - 0013-7952 .- 1872-6917. ; 324
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Tidskriftsartikel (refereegranskat)abstract
- Stability analysis of unsaturated landslide deposits requires reliable estimates of soil moisture and pore water pressure. However, modeled soil moisture and pore water pressure contain substantial uncertainties due to imperfect information on soil hydraulic properties. Due to the relatively high dimensionality, commonly used parameter optimization strategies can be significantly affected by equifinality problems. This study investigates the effectiveness of reducing parameter estimation dimensionality using soil pedo-transfer functions. Specifically, we first estimated soil hydraulic parameters using the traditional Generalized Likelihood Uncertainty Estimation (GLUE) method, with parameters randomly drawn from the entire space (refer to as GLUE-random). In a second strategy, we use the Rosetta 3 pedotransfer function to constrain soil hydraulic parameters (refer to as GLUE-Rosetta). The two methods were tested in a typical landslide deposit with in-situ measured soil moisture dynamics for inverse modeling. The GLUE-random estimated soil hydraulic parameters contained substantial uncertainties –resulting in poorly constrained soil water retention curves (SWCC) and hydraulic conductivity functions (HCF). As a result, the uncertainty bands of pore water pressure and slope stability can cross values with several orders of magnitudes. In contrast, GLUE-Rosetta provided well-constrained SWCC and HCF, which significantly reduce the uncertainties in pore water pressure and slope stability estimates. These results suggest that the Rosetta 3 pedotransfer function can significantly improve the reliability of soil hydraulic parameters by reducing the dimensionality of the optimization problem and high-quality prior information of soil hydraulic properties. In conclusion, Rosetta 3 can enhance the reliability of soil parameters estimates and the reliability of subsurface hydrology, which may benefit the development of landslide early-warning systems.
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| 3. |
- Zhang, Yue, et al.
(författare)
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Association between anthropometric indicators of obesity and cardiovascular risk factors among adults in Shanghai, China
- 2019
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Ingår i: BMC Public Health. - : BMC. - 1471-2458. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: To determine the optimal cut-off values and evaluate the associations of body mass index (BMI), waist circumference (WC) and waist-height ratio (WHtR) with cardiovascular disease (CVD) risk factors. Methods: A large-scale cross-sectional survey was conducted among 35,256 adults aged 20-74 years in Shanghai between June 2016 and December 2017. Receiver operating characteristic (ROC) analyses were conducted to assess the optimal cut-off anthropometric indices of CVD risk factors including hypertension, diabetes, dyslipidemia and hyperuricemia. Multivariate Logistic regression models were preformed to evaluate the odds ratio of CVD risk factors. Results: The area under the curve (AUC) of WHtR was significantly greater than that of BMI or WC in the prediction of hypertension and diabetes, and AUCs were higher in women than men. The optimal cut-off values of WHtR were approximately 0.51 in both sexes, while the cut-off values of BMI and WC were higher for men compared with women. The optimal cutoff values of BMI and WC varied greatly across different age groups, but the difference in WHtR was relatively slight. Among women, the optimal threshold of anthropometric indices appeared to increase with age for hypertension and diabetes. The odds ratio between anthropometric indices and CVD risk factors were attenuated with age. WHtR had the greatest odds ratio for CVD risk factors among adults under 60 years old except for women with hypertension, while among 60-74 years, BMI yielded the greatest odds ratio in terms of all CVD outcomes except for women with diabetes. Conclusions: WHtR had the best performance for discriminating hypertension and diabetes and potentially be served as a standard screening tool in public health. The associations between three anthropometric indices and CVD risk factors differed by sex and decreased with age. These findings indicated a need to develop age- and gender-specific difference and make effective strategies for primary prevention of CVDs.
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| 4. |
- Zhang, Yue, et al.
(författare)
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Prevalence and the association of body mass index and other risk factors with prediabetes and type 2 diabetes among 50,867 adults in China and Sweden: A cross-sectional study
- 2019
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Ingår i: Diabetes Therapy. - : Springer Science and Business Media LLC. - 1869-6953 .- 1869-6961. ; 10:6, s. 2061-2077
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Understanding socioeconomic differences for prediabetes and type 2 diabetes (T2DM) can offer guidance for the most effective development of both prevention and intervention programmes in different settings. This study aims to determine the prevalence and risk factors for prediabetes and T2DM and to explore the effect of high body mass index (BMI) on the probability of T2DM being present among adults in China and Sweden. Methods This study enrolled 25,356 adults (35-64 years old) from the Shanghai Survey in China and 25,511 adults (aged 40, 50, 60) from the Vasterbotten Intervention Programme in Sweden. Data on haemoglobin A1c, capillary fasting plasma glucose, 2-h plasma glucose and self-reported diagnoses of T2DM were used in the analysis. Multinomial logistic regression was used to examine the determinants of prediabetes and T2DM. The average predicted probabilities of T2DM developing or presenting were determined for the different ages and levels of BMI in each population. Results Chinese participants had a higher adjusted prevalence of T2DM (men 12.8% vs. 4.6%; women 10.6% vs. 3.1%) and prediabetes (men 12.4% vs. 12.2%; women 14.4% vs. 12.2%) than Swedish participants. Age, overweightedness/obesity, hypertension and a family history of diabetes were significant risk factors for prediabetes and T2DM. In both populations, the predicted probability of T2DM increased as the BMI increased in all age groups. At the same BMI level, Chinese participants were more likely to have T2DM compared to their Swedish counterparts. The average predicted probability of T2DM was less than 20% in nearly all age groups among Swedish women. Conclusions Chinese adults had the higher prevalence of prediabetes and T2DM and a higher probability of T2DM at the same BMI level compared with Swedish adults. These results indicate the importance of addressing the ongoing obesity epidemic as a matter of urgency in order to curb what has become an apparent diabetes epidemic in both countries.
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