ABSTRACT
Elymus nutans is an herbaceous plant that can be used to restore degraded alpine and subalpine ecosystems. Here, we evaluated how sowing density affects soil reinforcement and slope stabilization properties of vegetation-concrete structures. To investigate the optimal sowing density of E. nutans in vegetation-concrete applications for slope protection, six experimental treatments were established with different plant densities: control, I (1100 seeds/m2), II (2200 seeds/m2), III (3300 seeds/m2), IV (4400 seeds/m2), and V (5500 seeds/m2). Several parameters of plant growth in addition to soil reinforcement and slope stabilization properties were measured in each treatment, as well as the associations among parameters. As density increased, aboveground biomass continually increased, and plant heights, root surface areas, root lengths, and underground biomass all first increased and then decreased. In contrast, tiller numbers and the average root diameter gradually decreased with increasing density. Increased density also resulted in increased maximum water interception levels by aboveground stems and leaves. The maximum water interception by the aboveground stems and leaves was 41.75% greater in the highest density treatment (V) compared to the lowest density treatment (I). However, the enhancement of erosion resistance and soil shear strength first increased and then decreased as density increased, with maximal values observed in the medium-high density treatment (IV). Sowing density was highly correlated with aboveground biomass, plant heights, tiller numbers, and the maximum level of water interception by stems and leaves. Thus, sowing density directly influenced soil reinforcement and slope stabilization properties of aboveground plant components. However, density was not significantly correlated with belowground biomass, root lengths, root surface areas, the enhancement of erosion resistance, and soil shear strengths. Therefore, sowing density indirectly influenced soil reinforcement and slope stabilization of belowground plant components. Following from these results, we suggest that the optimal sowing density of E. nutans is approximately 4400 plants/m2 in their application within vegetation-concrete structures used for slope protection.
ABSTRACT
BACKGROUND: The ability to predict risk factors for blood transfusion after postpartum hemorrhage could enhance the performance of lifesaving procedures in patients who experience postpartum hemorrhage. Therefore, this study aimed to evaluate these risk factors and create a scoring system for blood transfusion evaluations and risk in obstetric patients. STUDY DESIGN AND METHODS: Diagnosis and blood transfusion data of 14,112 women who delivered between January 1, 2015, and December 31, 2015, were analyzed. A binary logistic regression model was used. We conducted univariate analyses of each risk factor as well as multivariable logistic regression analysis. Data of obstetric patients in 2016 validated the receiver operating characteristic curve. A risk prediction score was generated from the transfusion risk factor ß-coefficients in the multivariable logistic regression model. RESULTS: In total, 392 (2.94%) of 13,328 patients received transfusions. After multivariable adjustment, polyembryony, anemia, thrombocytopenia, preeclampsia, placenta previa, placental implantation, uterine scarring, uterine rupture, retained placenta, stillbirth, and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets) were significantly associated with perinatal transfusion. Heart disease and hemophilia were not related to transfusion risk. The blood transfusion risk evaluation table was well calibrated. CONCLUSIONS: Our retrospective analysis revealed that diagnoses including polyembryony, anemia, thrombocytopenia, preeclampsia, placenta previa, placenta implantation, uterine scarring, uterine rupture, retained placenta, stillbirth, and HELLP syndrome are significantly associated with perinatal transfusion and are risk factors for blood transfusion. The blood transfusion scoring system could be beneficial for evaluating blood transfusion risk.
