147 research outputs found
Effects of terracing on soil water and canopy transpiration of Pinus tabulaeformis in the Loess Plateau of China
Terracing has long been considered one of the most effective measures for soil water conservation and site improvement. However, few studies regarding the quantitative effects of terracing on soil water dynamics and vegetation water use efficiency were reported. To fill these knowledge gaps, in this study, soil water content and canopy transpiration from 2014 to 2015 were monitored in both terrace and slope environments in the semiarid Loess Plateau of China. Results showed that terracing had positive influences on soil water content among layers. Mean soil water content of the terrace site was 25.4% and 13.7% higher than that in the slope site in 2014 and 2015, and canopy transpiration at the terrace site increased by 9.1% and 4.8%, respectively. Canopy conductance at the terrace site was 3.9% higher than that at the slope site and it decreased logarithmically with the increase of vapor pressure deficit. This study highlighted the critical role of terracing in soil-water improvement and water-stress mitigation in semiarid environments. Thus, terracing has the potential to enhance sustainable vegetation restoration in water-limited regions
Flexible Informed Trees (FIT*): Adaptive Batch-Size Approach for Informed Sampling-Based Planner
In modern approaches to path planning and robot motion planning, anytime
almost-surely asymptotically optimal planners dominate the benchmark of
sample-based planners. A notable example is Batch Informed Trees (BIT*), where
planners iteratively determine paths to groups of vertices within the
exploration area. However, maintaining a consistent batch size is crucial for
initial pathfinding and optimal performance, relying on effective task
allocation. This paper introduces Flexible Informed Tree (FIT*), a novel
planner integrating an adaptive batch-size method to enhance task scheduling in
various environments. FIT* employs a flexible approach in adjusting batch sizes
dynamically based on the inherent complexity of the planning domain and the
current n-dimensional hyperellipsoid of the system. By constantly optimizing
batch sizes, FIT* achieves improved computational efficiency and scalability
while maintaining solution quality. This adaptive batch-size method
significantly enhances the planner's ability to handle diverse and evolving
problem domains. FIT* outperforms existing single-query, sampling-based
planners on the tested problems in R^2 to R^8, and was demonstrated in
real-world environments with KI-Fabrik/DARKO-Project Europe.Comment: 8 pages,6 figure
Global synthesis of the classifications, distributions, benefits and issues of terracing
For thousands of years, humans have created different types of terraces in different sloping conditions, meant to mitigate flood risks, reduce soil erosion and conserve water. These anthropogenic landscapes can be found in tropical and subtropical rainforests, deserts, and arid and semiarid mountains across the globe. Despite the long history, the roles of and the mechanisms by which terracing improves ecosystem services (ESs) remain poorly understood. Using literature synthesis and quantitative analysis, the worldwide types, distributions, major benefits and issues of terracing are presented in this review. A key terracing indicator, defined as the ratio of different ESs under terraced and non-terraced slopes (δ), was used to quantify the role of terracing in providing ESs. Our results indicated that ESs provided by terracingwas generally positive because themean values of δ were mostly greater than one. The most prominent role of terracing was found in erosion control (11.46 ± 2.34), followed by runoff reduction (2.60 ± 1.79), biomass accumulation (1.94 ± 0.59), soil water recharge (1.20±0.23), and nutrient enhancement (1.20±0.48). Terracing, to a lesser extent, could also enhance the survival rates of plant seedlings, promote ecosystem restoration, and increase crop yields.While slopes experiencing severe human disturbance (e.g., overgrazing and deforestation) can generally become more stable after terracing, negative effects of terracing may occur in poorly-designed or poorly-managed terraces. Among the reasons are the lack of environmental legislation, changes in traditional concepts and lifestyles of local people, as well as price decreases for agricultural products. All of these can accelerate terrace abandonment and degradation. In light of these findings, possible solutions regarding socio-economic changes and techniques to improve already degraded terraces are discussed
Effects of the gastric juice injection pattern and contraction frequency on the digestibility of casein powder suspensions in an in vitro dynamic rat stomach made with a 3D printed model
Previously, we have prepared a version of the dynamic in vitro rat stomach system (DIVRS-II or Biomimic Rat II). It was constructed and tested by showing similar digestive behaviors with those occurred in vivo. In the present work, a 3D-printed plastic mold was employed to create highly repeatable silicone rat stomach model. It has been seen to have shortened the time to handcraft a model like that used in DIVRS-II. The maximum mechanical force of the current stomach model generated by rolling extrusion is found to be more stable probably due to the more uniform wall thickness of the new model. Then the effects of the simulated gastric secretion patterns and contraction frequency of the system on the in vitro digestibility of casein powder suspensions were investigated. The results have shown that the location of the gastric secretion injection has an impact on experimental digestibility. The position of rolling-extrusion area, established at the central part of glandular portion (stomach B), displayed the highest digestibility compared to that at the other locations. Furthermore, the extent of digestion was positively correlated with the contraction frequency of the model stomach system, with the maximum frequency of 12cpm giving the highest digestibility. This highest digestibility is almost the same as the average value found in vivo. The better digestive performance produced by optimizing the gastric secretion pattern and contraction frequency may be both resulted from the improved mixing efficiency of the food matrix with digestive juice. This study shows that it is possible to achieve what in vivo in a simulated digestion device, which may be used for future food and nutrition studies in vitro
Global synthesis of the classifications, distributions, benefits and issues of terracing
For thousands of years, humans have created different types of terraces in different sloping conditions, meant to mitigate flood risks, reduce soil erosion and conserve water. These anthropogenic landscapes can be found in tropical and subtropical rainforests, deserts, and arid and semiarid mountains across the globe. Despite the long history, the roles of and the mechanisms by which terracing improves ecosystem services (ESs) remain poorly understood. Using literature synthesis and quantitative analysis, the worldwide types, distributions, major benefits and issues of terracing are presented in this review. A key terracing indicator, defined as the ratio of different ESs under terraced and non-terraced slopes (δ), was used to quantify the role of terracing in providing ESs. Our results indicated that ESs provided by terracingwas generally positive because themean values of δ were mostly greater than one. The most prominent role of terracing was found in erosion control (11.46 ± 2.34), followed by runoff reduction (2.60 ± 1.79), biomass accumulation (1.94 ± 0.59), soil water recharge (1.20±0.23), and nutrient enhancement (1.20±0.48). Terracing, to a lesser extent, could also enhance the survival rates of plant seedlings, promote ecosystem restoration, and increase crop yields.While slopes experiencing severe human disturbance (e.g., overgrazing and deforestation) can generally become more stable after terracing, negative effects of terracing may occur in poorly-designed or poorly-managed terraces. Among the reasons are the lack of environmental legislation, changes in traditional concepts and lifestyles of local people, as well as price decreases for agricultural products. All of these can accelerate terrace abandonment and degradation. In light of these findings, possible solutions regarding socio-economic changes and techniques to improve already degraded terraces are discussed
The Distribution and Accessibility of Urban Parks in Beijing, China: Implications of Social Equity
Influence of landscape features on urban land surface temperature: scale and neighborhood effects
The relationships between land use and soil conditions in the hilly area of the loess plateau in northern Shaanxi, China
Greening China naturally
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in AMBIO: A Journal of the Human Environment 40 (2011): 828-831, doi:10.1007/s13280-011-0150-8.China leads the world in afforestation, and is one of the few countries whose forested area is increasing. However, this massive ‘‘greening’’ effort has been less effective than expected; afforestation has sometimes produced unintended environmental, ecological, and socioeconomic consequences, and has failed to achieve the desired ecological benefits. Where afforestation has succeeded, the approach was tailored to local environmental
conditions. Using the right plant species or species composition for the site and considering alternatives such as grassland restoration have been important success factors. To expand this success, government policy should shift from a forest-based approach to a results-based approach. In addition, long-term monitoring must be implemented to provide the data needed to develop a cost-effective, scientifically informed restoration policy.This work was supported by the Fundamental Research Funds for the Central Universities (HJ2010-3) and the CAS/ SAFEA International Partnership Program for Creative Research Teams of ‘‘Ecosystem Processes and Services’’
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