Hysteresis resulting in forestry heat storage underestimation: A case study of plantation forestry in northern China.

Heat storage (Q) is an important component of the near-surface energy balance, and has been increasingly considered in recent energy balance studies. Studies have revealed that the hysteresis of heat storage was always been ignored, which leaded to the underestimation of heat storage proportion in energy balance. So, for further understanding the role of hysteresis effect in forestry heat storage, an observation experiment of heat storage in forestry of Pinus sylvestris var. mongolica Litv forestry - a common species in northern China - was conducted. Heat storage in the atmosphere beneath canopy, in the canopy biomass, and in the soil above a soil heat-flow plate were monitored continuously, to determine the distribution of stored heat, and solar radiation was simultaneously monitored to verify the hysteresis of heat storage versus radiation. Seasonal variations were separately analyzed to further clarify phenological effect on hysteresis. Correlation relationship was tested of lag time and underestimated energy versus climatic factors and physiological characteristics, for clarifying the reasons that resulting in hysteresis differences under different experimental day. The main results were as follows: (1) Hysteresis exists in heat storage and the lag time was 3.79 h in our study area; (2) The evaluation of hysteresis is crucial to avoid an underestimation of heat storage. Correction of lag time increases the heat storage proportion in R from 3.78% to 8.48%; (3) Increasing of air temperature and humility daily differences will enhance the underestimated energy. High radiation condition will weak the underestimation on heat storage and short the lag time. Soil moisture and leaf area index were not effect energy hysteresis significantly in sandy vegetation. Climatic factors were the main reason that resulting in the differences of hysteresis. This study helps to improve understanding energy transmitting in canopy and offering a new view in solving surface energy imbalance.

Application of Boundary Layer Displacement Thickness in Wind Erosion Protection Evaluation: Case Study of a Salix psammophila Sand Barrier.

Since the establishment of blown sand physics, surface roughness has been widely used in current research to indicate the ability of a surface to resist wind erosion and to evaluate the windproof effect of protective measures. However, since the calculation of surface roughness can result in different values and its applicability is poor, there are disadvantages to its use. Therefore, it is proposed that the boundary layer displacement thickness should be used rather than roughness as an indicator to solve such problems. To analyze the new indicator's accuracy and applicability when evaluating the effect of protective measures, a wind tunnel simulation experiment on a typical mechanical protection measure commonly used for sand control in China was conducted. Indicators of roughness and boundary layer displacement thickness were compared in evaluating the windproof performance of a Salix psammophila sand barrier of differing heights, side lengths, and porosities. The wind speed acceleration rate and effective protection area, which can directly reflect the protective effect of a sand barrier, were analyzed as evaluation criteria. The results show that roughness can only reflect the influence of height on the windbreak effect of sand barriers, whereas the boundary layer displacement thickness accurately showed the influence of height, side length, and porosity on the windproof effect of the sand barriers. Compared with roughness, the boundary layer displacement thickness was more strongly correlated with the effective protection area. Therefore, the boundary layer displacement thickness, rather than roughness, should be used as a new indicator when evaluating the windproof effect of protective measures.

Effect of Straw Checkerboards on Wind Proofing, Sand Fixation, and Ecological Restoration in Shifting Sandy Land.

Due to their simple layout and adaptability to various environments, straw checkerboards are widely used to control windblown sand in China. To fully understand the wind proofing and sand-fixing benefits of different board specifications, and to determine the restorative effects of straw checkerboard, we tested different sizes of checkerboard, determined their performance as a windbreak and in trapping shifting sand, and constructed models based on wind tunnel tests, enabling the wind speed flow field to be analysed. We also sampled the soil in areas where straw checkerboards had been established for several years and analysed the trends in soil physical and chemical properties over time. We found that all sizes of straw checkerboard effectively reduced the wind speed near the surface and formed a protected area, with the best protective effect achieved for a one-meter board. All sizes of straw checkerboard effectively intercepted windblown sand to form surface accumulation, with the one-meter board again showing the best performance. The use of a straw checkerboard also effectively improved the physical and chemical properties of soil and promoted ecological restoration. These results indicate that straw checkerboards are a low-cost engineering measure that could play an important role in desertification control and the ecological restoration of sandy land ecosystems.

How the Plant Temperature Links to the Air Temperature in the Desert Plant Artemisia ordosica.

Plant temperature (Tp) is an important indicator of plant health. To determine the dynamics of plant temperature and self-cooling ability of the plant, we measured Tp in Artemisia ordosica in July, in the Mu Us Desert of Northwest China. Related factors were also monitored to investigate their effects on Tp, including environmental factors, such as air temperature (Ta), relative humidity, wind speed; and physiological factors, such as leaf water potential, sap flow, and water content. The results indicate that: 1) Tp generally changes in conjunction with Ta mainly, and varies with height and among the plant organs. Tp in the young branches is most constant, while it is the most sensitive in the leaves. 2) Correlations between Tp and environmental factors show that Tp is affected mainly by Ta. 3) The self-cooling ability of the plant was effective by midday, with Tp being lower than Ta. 4) Increasing sap flow and leaf water potential showed that transpiration formed part of the mechanism that supported self-cooling. Increased in water conductance and specific heat at midday may be additional factors that contribute to plant cooling ability. Therefore, our results confirmed plant self-cooling ability. The response to high temperatures is regulated by both transpiration speed and an increase in stem water conductance. This study provides quantitative data for plant management in terms of temperature control. Moreover, our findings will assist species selection with taking plant temperature as an index.

Effect of Shuganlipi decoction on Th1/Th2 cytokines in patients with chronic hepatitis B / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of Shuganlipi decoction on Th1/Th2 cytokines, liver function and HBV replication in patients with chronic hepatitis B (CHB).</p><p><b>METHODS</b>Eighty-six confirmed CHB cases were randomly divided into control group (n=42) and experimental group (n=44) for treatment with routine western medication and additional treatment with Shuganlipi decoction, respectively. The production of IFN-γ, IL-2, IL-6, IL-10 and liver function, HBV DNA, and HBeAg were detected in all the patients.</p><p><b>RESULTS</b>The total response rate to the treatment was significantly higher in the experimental group than in the control group (78.13% vs 57.14%, P<0.01). ALT, AST, TBIL and ALB were all improved obviously in the two groups after the treatments (P<0.01). In terms of ALT and ALB, the experimental group showed more obvious improvement than the control group(P<0.05). The treatments also resulted in significant increases of IFN-γ and IL-2 levels and reductions of IL-6 and IL-10 levels in the two groups (P<0.01).</p><p><b>CONCLUSION</b>Shuganlipi decoction can improve the liver function and activity of Th1/Th2 cytokines to promote the clearance of liver cell HBV infection.</p>