Driving Forces and Their Effects on Water Conservation Services in Forest Ecosystems in China

Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service （IN-DI-ESS） driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis （TS-DEA） to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1） Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2） Spearman＇s rank correlation test was performed to compare the overall effectiveness in two periods： stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-D1-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.

Study on Water and Soil Conservation Effects of Grassland Based on Live Vegetation Volume at Various Time Scales

Based on the observation data of rainfall,vegetation,runoff and sediment yield in the experimental plots located in Hetian Town,Changting County of Fujian Province during 2007-2010,the changing characteristics and interrelation of live vegetation volume of grass,rainfall parameters,and water(soil)conservation effect RE(SE)were analyzed at four time scales of rainfall event,month,season,and year.The results showed that with the increase of time scales,the rainfall and vegetation indicators increased or decreased more or less,and the variation range of RE was small,while SEslowly decreased.The mean REchanged by 10%-20% at different time scales,and the observed water conservation effect of the grassland was the best at season scale while the worst at year scale.The soil conservation effect of the grassland was the best at month scale and the worst at season scale.The water conservation effect of the grass was mainly controlled by rainfall factors,including rainfall duration and precipitation at rainfall event scale,and the maximum intensity of precipitation within 30 min at longer time scales.However,the soil conservation effect of the grass was mainly controlled by vegetation factors,including the contribution of the litter on soil surface at rainfall event scale,the interaction of rainfall and vegetation at month and season scales,and the live vegetation volume of the grass at year scale.Consequently,at different time scales,the factors influencing water and soil conservation changed and interacted,and the observed water and soil conservation effects were also different,indicating that the influence of time scales deserves attention in both research and management practices.

Effects of Conservation Tillage on Crop Yield: a Case Study in the Part of Typical Ecological Zones in China

To evaluate the effects of different conservation tillage modes on crop yield in various ecological regions, we interviewed peasant households in the Northeast China Plain, North China Plain, Chengdu Plain, and Northwest China Oasis, China, to analyze the influencing factors of the tillage methods on crop yield. An index set was determined from seven yield parameters based on expert consultation and relevant literature. A comprehensive evaluation of conservation tillage methods in the various ecological regions was carried out using fuzzy theory. The approaches with the highest scores were identified for each region： wide and narrow rotation planting with high stubble standing retention in the Northeast China Plain; seeding after rotary tilled of wheat under corn straw mulching and no-tillage seeding of corn and other crops under wheat straw mulching in the North China Plain; no tillage with high stubble retention in the Northwest China Oasis; and no-tillage seeding of wheat and other crops under rice straw mulching in Chengdu Plain. These research data provide a useful guide for the selection of conservation tillage methods for optimum yields in different regions of China.

Contemporary Global Issue of Rising Water Scarcity for Agriculture: The Quest for Effective and Feasible Soil Moisture and Free-Water Surface Conservation Strategies

There is the need to take seriously the task of conserving soil moisture in agricultural fields and free-water surfaces in reservoirs, especially in recent years of climate change. Many strategies exist for achieving this task and improving the productivity of arable soils. These strategies traditionally come under biological and physical or mechanical measures. Some other relatively new techniques operate neither on physical nor on biological principle. All these measures which operate on different principles frequently overlap. The principles involved, together with the prospects and constraints of the key techniques of conserving soil moisture found in the literature, are reviewed in this paper. Among other considerations, the effectiveness and/or practicability of any one of the techniques depend upon soil type, topography, climate, scale of production, level of technology, and socio-economic status. Such agronomic practices as conservation tillage and live vegetation mulch that maintain infiltration rates often appear to be more beneficial in the long run than engineering structures, especially those that lead to blocking of waterways on the soil surface. However, this review reveals that none of the soil moisture conservation strategies could be credited as universally applicable. Consequently, an integrated approach to soil water management and conservation, where feasible, is considered more appropriate. This is because the different principles involved in the techniques identified to be compatible would readily complement and strengthen one another. Such a multi-mechanistic approach is expected to result in improved efficacy in conserving water resources in soils and open reservoirs.

Effect of Different Amendments on Nitrogen Conservation During Simulated Composting

The objectives of this study were to evaluate the effects of different dosages of three amendments—peat,superphosphate,mixture of Mg(OH)2+H3PO4(Magnesium Hydroxide and Phosphorus Acid)on N(Nitrogen)conservation.The simulated composting experiment was carried out in a constant temperature water bath with pig manure and corn straw.The results showed that the ammonia volatilization could be inhibited to some extent under the treatments with fixing agents.Under the same simulated composting conditions,the nitrogen fixation effect of the three kinds of fixatives with the same proportion was as follows:Mg(OH)2+H3PO4>superphosphate>peat.The fixation effect of N increased with the increase of the additives.The N fixation rate of Mg(OH)2+H3PO4 treatment was up to 66%.Compared with the CK(Control Group),the amount of cumulative ammonia emission decreased by 90.3% and the TN(Total Nitrogen)content increased by 39.31% in this treatment.Compared with other two kinds of fixing agents,Mg(OH)2+H3PO4 treatment could not only control N loss in composting process,improve the N nutrient content of compost products,but also could increase P(Phosphorus)and Mg(Magnesium)nutrients.Therefore,it had more popularization value and application prospect.

Safe conservation and utilization of peanut germplasm resources in the Oil Crops Middle-term Genebank of China

Peanut(Arachis hypogaea L.)is an important oil and cash crop in the world.Peanut germplasm collected in China are abundant,which provides important material guarantee for peanut breeding and industrial development.Here,the safe conservation technology and indicators of peanut germplasm resources in the Oil Crops Middleterm Genebank of China were expounded from three processes of storage,monitoring,reproduction and renewal.We summarized and reviewed the situation of conservation and utilization of peanut germplasm resources in the Middle-term Genebank in the past 20 years.The future research direction of peanut resources in the Oil Crops Middle-term Genebank of China is prospected.

Vegetation structure and edaphic factors in veredas reflect different conservation status in these threatened areas

Background:In Cerrado humid areas,veredas are considered as hygrophilous communities,marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones.Changes in veredas ecosystems due to drought and changes in the water table,which represent important areas for biodiversity maintenance in the Brazilian cerrado,can lead to the emergence of new landscapes and ecosystems.Assuming that the veredas are changed in species composition due to anthropogenic factors,in this study,we evaluated the flora composition and described the current vegetation profile of two veredas under different disturbances levels that are located in the north of Minas Gerais State,Brazil.Results:Altogether,2,268 individuals of 91 species belonging to 36 families were recorded.Our results demonstrated that the studied veredas were floristically different in terms of the arboreous-shrubby species composition,richness,and diversity.Despite the hygrophilous forest formations and open areas in the two veredas present typical species from these environments(same species with high importance values),the drought in the water table caused an expansion of Cerrado species in the open areas and in the hygrophilous forest.Furthermore,in the hygrophilous forest there was an increase in the abundance of species that occur in less saturated soils.Conclusion:Our results demonstrate that the studied veredas are changing in species composition due to anthropogenic factors which leads to the drought of these formations(water balance effect).These anthropogenic effects cause a modification with the expansion and increase in the abundance of typical species of other areas of Cerrado and resistant to less saturated soils,leading to the veredas collapse.Finally,future studies should investigate other veredas on a broader scale to detect changes in the water table that lead to a consequent change in vegetation structure.In this way,we will have support for the conscientious management and conservation of these areas that represent equilibrium places for the Cerrado biome.

Conservative management of cervical pregnancy with intramuscular administration of methotrexate and KCl injection: Case report and review of the literature

We report the case of a cervical pregnancy successfully treated with intramuscular injection of methotrexate(MTX) and intramniotic administration of potassium chloride. A 41-year-old woman was admitted to our Department with the suspicion of ectopic pregnancy. Transvaginal ultrasound revealed empty endometrialcavity, gestational sac within the cervical canal and embryonic echo measuring crown rump length 1.5 mm. Serum beta human chorionic gonadotropine(β-HCG) was measured 28590 IU/L. No cardiac activity was detected. The diagnosis of a cervical pregnancy was made. Patient was treated with intramuscular administration of methotrexate(50 mg/m2) in combination with ultrasoundguided intramniotic injection of KCl(2 meq/mL). Gradual decrease of β-HCG levels as well as ultrasound observation of collapsed gestational sac was observed. No curettage was necessitated. Patient was discharged on day 10 th and was set in follow-up on a weekly basis. β-HCG values were measured < 10 IU/L on 56 th day after MTX administration. Intramuscular administration of MTX may be effective in treatment of cervical pregnancy without additional interventional measures.

Evaluation of Ecological Effectiveness of Protected Areas in Northwest China

Protected areas(PAs) have experienced explosive growth in Northwest China over the last three decades, but their effectiveness in representing regional ecological system diversity has not attracted considerable attention. Low effectiveness would exacerbate the conservation-development conflicts, particularly those that arise as a result of the Great Western Development Strategy(GWDS). Thus, an assessment of the effectiveness of the PA network has become quite important. We proposed natural vegetation communities to represent regional ecological system diversities, and proposed Global 200 Priority Ecoregions, Important Bird Areas, and ecosystem function regions to represent important conservation areas. To determine their effectiveness, we studied the extent to which ecological system diversities and important conservation areas are represented by the existing 96 PAs. Our results indicated that the total coverage of vegetation communities in PAs in Northwest China is not sufficiently comprehensive. As the PA system has expanded, the growth in the total area of the PAs has been greater than that of their vegetation community richness. While most of the important conservation areas are covered by PAs, some regions have not yet reached the 10% threshold; further, PAs are distributed unevenly and conservation gaps remain in the region. Therefore, these regions should receive more attention when planning new PAs. It is vital that more biodiversity datasets and assessment of ecosystem function regions are integrated in order to provide a basis for the government to formulate appropriate protection and development strategies.

KINETIC FUNCTIONS IN MAGNETOHYDRODYNAMICS WITH RESISTIVITY AND HALL EFFECT

We consider a nonlinear hyperbolic system of two conservation laws which arises in ideal magnetohydrodynamics and includes second-order terms accounting for magnetic resistivity and Hall effect. We show that the initial value problem for this model may lead to solutions exhibiting complex wave structures, including undercompressive nonclassical shock waves. We investigate numerically the subtle competition that takes place between the hyperbolic, diffusive, and dispersive parts of the system. Following Abeyratne, Knowles, LeFloch, and Truskinovsky, who studied similar questions arising in fluid and solid flows, we determine the associated kinetic function which characterizes the dynamics of undereompressive shocks driven by resistivity and Hall effect. To this end, we design a new class of ＂schemes with eontroled dissipation＂, following recent work by LeFloch and Mohammadian. It is now recognized that the equivalent equation associated with a scheme provides a guideline to design schemes that capture physically relevant, nonclassical shocks. We propose a new class of schemes based on high-order entropy conservative, finite differences for the hyperbolic flux, and high-order central differences for the resistivity and Hall terms. These schemes are tested for several regimes of （co-planar or not） initial data and parameter values, and allow us to analyze the properties of nonclassical shocks and establish the existence of monotone kinetic functions in magnetohydrodynamics.

Significance of ipsilateral breast tumor recurrence after breast conserving treatment: role of surgical removal

Objective： To analyze the pattern over time （dynamics） of further recurrence and death after ipsilateral breast tumor recurrence （IBTR） in breast cancer patients undergoing breast conserving treatment （BCT）. Methods： A total of 338 evaluable patients experiencing IBTR were extracted from a database of 3,293 patients undergoing BCT. The hazard rates for recurrence and mortality throughout 10 years of follow-up after IBTR were assessed and were compared to the analogous estimates associated to the primary treatment. Results： In a time frame with the time origin at the surgical treatment for IBTR, the hazard rate for further recurrence displays a bimodal pattern （peaks at the second and at the sixth year）. Patients receiving mastectomy for IBTR reveal recurrence and mortality dynamics similar to that of node positive （N＋） patients receiving mastectomy as primary surgery, apart from the first two-three years, when IBTR patients do worse. If the patients with time to IBTR longer than 2.5 years are considered, differences disappear. Conclusions： The recurrence and mortality dynamics following IBTR surgical removal is similar to the corresponding dynamics following primary tumor removal. In particular, patients with time to IBTR in excess of 2.5 years behave like N＋ patients following primary tumor removal. Findings may be suitably explained by assuming that the surgical manoeuvre required by IBTR treatment is able to activate a sudden growing phase for tumor foci most of which, as suggested by the systemic model of breast cancer, would have reached the clinical level according to their own dynamics.

The influence of defects on the effective Young's modulus of a defective solid

It is difficult to establish structure-property relationships in a defective solid because of its inhomogeneous-geometry microstructure caused by defects. In the present research, the effects of pores and cracks on the Young’s modulus of a defective solid are studied. Based on the law of the conservation of energy, mathematical formulations are proposed to indicate how the shape, size, and distribution of defects affect the effective Young’s modulus. In this approach, detailed equations are illustrated to represent the shape and size of defects on the effective Young’s modulus. Different from the results obtained from the traditional empirical analyses, mixture law or statistical method, for the first time, our results from the finite element method （FEM） and strict analytical calculation show that the influence of pore radius and crack length on the effective Young’s modulus can be quantified. It is found that the longest crack in a typical microstructure of ceramic coating dominates the contribution of the effective Young’s modulus in the vertical direction of the crack.

Study of the insulation effect of freezing apparatuses

In-situ tests and numerical manipulations were conducted for comparison of superior/inferior quality of casing-tube-vacuumized insulation and polyurethane insulation of fi＇eezing apparatuses in relation to non-uniform cold distribution in the multi-coil fi＇eez- ing layout and the contradiction between large-coil diameter layout of the freezing holes and stability of the headfi＇ame base. Tests show that： （1） under current technology, vacuumized insulation is of short duration due to lack of appropriate applied vacuum; （2） after the freezing pipe is insulated with polyurethane, the temperature gradient is less than no insulation, and the temperature dif- ference between insulated and non-insulated apparatuses is stable as the freezing period increases. Finally, it is pointed out that polyurethane insulation is quite efficient in present technical freezing construction. Keywords： freezing pipe; insulation effect; polyurethane; energy conservation

Analytical modelling of the mechanical damage of soil induced by lightning strikes capturing electro-thermal,thermo-osmotic,and electro-osmotic effects

This article presents a mathematical model for simulating the mechanical behaviour of lightning strikes and analysing the resulting damage to the soil.This article focuses on the electro-thermal effect and seepage caused by lightning strikes in particular.Then,a numerical model based on the conservation laws of momentum,mass and energy is developed for soil subjected to lightning strikes.Comparisons to field observations and theoretical calculations are used to demonstrate the efficacy and accuracy of numerical simulations.The findings demonstrate that lightning strikes can cause soils to experience both seepage force and heat stress.Under the calculative condition of this article:by increasing the intrinsic permeability of the soil,k_(p)(≥10^(-10)m^(2)),the seepage force can be effectively reduced,hence reducing the risk of lightning strikes;improving the electrical conductivity of the soil β(≥10^(-1) S/m^(2))and lowering its thermal expansion coefficient(≤10^(-6)K^(-1))can greatly reduce the damage caused by lightning strikes to the soil.The preceding investigations demonstrate that the suggested model is capable of evaluating mechanical damage caused by lightning in the soil,and the findings contribute to a better understanding of soil mechanical response to lightning strikes.

New Insights on Energy Conserved Planar Motion

The planar motion of a particle within an arbitrary potential field is considered.The particle is additionally subject to an external force wherein the applied thrust-acceleration is constrained to remain normal to the velocity vector.The system is thus non-conservative but since the thrust force is non-working,the total energy is a conserved quantity.Under this setting,a major result of fundamental importance is established in this paper:that the flight direction angle(more precisely,the sine of the angle between the position and velocity vectors)is shown to always satisfy a linear first-order differential equation with variable coefficients that depend upon the underlying potential function.As a consequence,an analytical solution for the flight direction angle can be obtained directly in terms of the particle’s distance from the center of the field for a significant number of special cases for the potential function.In the case of J2 perturbed spacecraft motion within equatorial orbits,the problem is reduced to that of solving an incomplete elliptic integral.Another important implication of the main result established here is that motion problems subject to velocity-normal thrusting can always be reduced to the study of equivalent single degree-of-freedom conservative systems with an effective potential function.The paper concludes with various examples of both academic and practical interest including the study of bounded two-body Keplerian orbits and hodograph interpretetions.

Analysis of Conservative and Magnetically Induced Electric Fields in a Low-Frequency Birdcage Coil

Numerical methods are used to evaluate variations of the electromagnetic fields generated by a head-sized birdcage coil as a function of load (“loading effect”). The loading effect was analyzed for the cases of a coil loaded with a conductive cylindrical sample, a dielectric cylindrical sample, and an anatomically precise head model. Maxwell equations were solved by means of finite difference time domain (FDTD) method conducted at 12.8, 64, and 128 MHz. Simulation results indicate that at 12.8 MHz the conservative electric field (Ec) caused by the scalar electric potentials between the coil and the load or within the load was significantly higher than the magnetically-induced electric field (Ei) and was the major component of the total electric field (Etotal). The amplitudes of Ec and Etotal are seen to be lower within a sample than at a corresponding location in an empty coil, but approximately 65% higher in the space between coil and sample than at a corresponding location in an empty coil. This is due to polarization effects generating an additional scalar potential parallel to the original field. The increased electric field between coil and sample may cause increased power deposition at the surface of the sample and may affect the RF-induced currents in external leads used for physiological recording, i.e. ECG, during MRI scanning.

黑龙江省保护性耕作技术实施效果统计分析

为跟踪东北黑土地保护性耕作行动计划实施状况,促进保护性耕作技术规范应用,对黑龙江省机械化保护性耕作技术实施情况进行抽样评估具有重要意义。为此,采用五点取样法实测调查抽样县(区)实施保护性耕作地块的保护性耕作方式、动土情况及秸秆覆盖率,调查并对比分析保护性耕作地块与相邻的非保护性耕作地块玉米株高、杂草及病虫发生情况。结果表明:黑龙江省采用免耕播种和少耕播种方式实施保护性耕作技术,在玉米生长中后期动土率低于50%的实施保护性耕作技术地块占总调研地块的75%,秸秆覆盖率大于30%的实施保护性耕作地块比例占60%;实施免耕或少耕等保护性耕作技术地块的玉米株高、杂草及病虫发生机率与相邻非保护性耕作地块差异不大,整体效果较好,尤其在遭受大风和强降雨灾害地区,实施保护性耕作技术种植的玉米抗倒伏优势明显;实施保护性耕作技术可以减少机械生产作业环节,降低农业生产成本,有效保护黑土资源,在黑龙江省具有较好的推广前景。

三维土工网边坡防护水土保持能力研究

路基边坡防护工程可减轻降雨对坡面土体的侵蚀作用,为深入研究坡面防护材料水土保持能力的定量表征方法,通过室内人工降雨边坡侵蚀模型试验,分析不同降雨强度和不同三维土工网防护下路基边坡的降雨侵蚀规律,提出三维土工网水土保持能力的试验测定方法及相关系数计算公式。研究结果表明:三维土工网防护边坡泥沙流失干质量明显小于相同条件下不设防边坡泥沙流失干质量,土工网防护在减少边坡侵蚀量的同时,有利于边坡侵蚀进程的快速稳定,但土工网的水土保持能力随雨强增大急剧下降。泥沙流失速度随着降雨的持续而逐渐减小,后期趋于收敛稳定,侵蚀历程采用指数函数拟合具有较好的相关性。建议设防边坡的试验降雨时间不少于70 min,不设防的边坡试验降雨时间不小于100 min。水土保持能力系数随雨强的增大呈对数函数关系减小,雨强超过100 mm/h时水土保持能力系数实测值与对数函数拟合值差异较大,建议在测定材料水土保持能力系数时雨强取20~100 mm/h,可取50 mm/h作为标准试验雨强。泡面类三维土工网水土保持能力显著优于普通三维土工网,而双泡面的三维土工网优于单泡面三维土工网。试验条件下凹凸泡面三维土工网的水土保持能力系数主要分布在1.71~3.03,建议50 mm/h雨强三维土工网水土保持能力系数不应小于1.5。

Effectiveness Assessment of Soil Erosion Critical Source Areas for Soil and Water Conservation

Critical source areas （CSAs）, characterized by severe soil erosion and high sediment yield, are considered to have a high priority for conservation. How to identify CSAs and assess the effectiveness of conservation practices is a key issue in site-specific watershed management. The Soil and Water Assessment Tool （SWAT） model is a useful tool for site-specific conservation practices design and several studies have attempted to identify CSAs based on watershed models. However, limited research has reported about the effectiveness of conservation practices targeting CSAs. The aim of this study was to assess the effectiveness of conservation pracrices targeted on CSAs using the SWAT model. CSA was firstly identified based on the 4-year average yearly erosion of each HRU. Appropriate soil conservation practices were then designed for the CSAs. A scenario with conservation practices for the whole watershed was also established as the contrasting counter parts scheme and then compared to the outcome of CSA-targeted conservation practices. The result shows that SWAT can accurately simulate sediment yield in the study area. CSAs were mainly located in slope farmland areas and steep gullies, coinciding with the distribution of land use and slope. The identified CSA covered 20% of the HRUs and contributed on average 44% of sediment yield. Conservation practices targeting CSAs had higher sediment reduction effectiveness （24 115 t km-2 y-1） than conservation practice covering the whole watershed （20 290 t km-2 y-1）. Thus conservation practices targeting CSAs are more effective than broad conservation practices. We conclude that soil conservation practices focusing on CSAs do increase sediment reduction effectiveness. Targeting the placement of soil conservation practices based on the CSAs concept will assist water quality control in watersheds.