整合信息技术 显现新型教学设计——《生态平衡》教学设计

一、教学内容 苏教版《科学》六下第四单元《共同的家园》的第四课《生态平衡》。 二、教学分析 1、教学内容分析： 本课是苏教版《科学》六下第四单元《共同的家园》的第四课。本课在前三课的基础上，引入生态平衡的概念。通过引领学生认识生态平衡的重要性，分析生态失衡的危害性，以及开展模拟生态的活动，带领学生学习环境科学的初级知识，

Species-diversified plant cover enhances orchard ecosystem resistance to climatic stress and soil erosion in subtropical hillside

Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang) orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 15×8m^2 and separated by 2m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positive ecological effects on citrus orchard ecosystem stability.

Determination of a Reasonable Percentage for Ecological Water-Use in the Haihe River Basin, China

An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key aspects for the ecological water requirement （EWR） were analyzed, involving i） the EWR for river system, ii） the EWR for wetlands and lakes, and iii） the EWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of EWR. The results showed that the total ecological water demand in the region, was about 3.47-14.56 billion m^3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approached 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, respectively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was estimated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

Existence for positive steady states of an eco-epidemiological model

An eco-epidemiological model with an epidemic in the predator and with a Holling type Ⅱ function is considered.A system with diffusion under the homogeneous Neumann boundary condition is studied.The existence for a positive solution of the corresponding steady state problem is mainly discussed.First,a prior estimates（positive upper and lower bounds） of the positive steady states of the reaction-diffusion system is given by the maximum principle and the Harnack inequation.Then,the non-existence of non-constant positive steady states by using the energy method is given.Finally,the existence of non-constant positive steady states is obtained by using the topological degree.

Soil Water Hysteresis at Low Potential

Knowledge of the soil water characteristic curve is fundamental for understanding unsaturated soils.The objective of this work was to find scanning hysteresis loops of two fine textured soils at water potentials below wilting point.This was done by equilibration over NaCl solutions with water potentials of-6.6 to-18.8 MPa at 25℃.When cycled repeatedly through a series of potentials in the range noted previously both soils exhibited a hysteresis effect.The experimental differences in water content between the drying and wetting soils at the same water potential were much too large to be accounted for by failure to allow sufficient time to attain equilibrium as predicted by the exponential decay model.The wetting versus drying differences were relatively small,however,at only 4 mg g-1 or less in absolute terms and about 3% of the mean of wetting and drying,in relative terms.Hysteresis should be a consideration when modeling biological and physical soil processes at water contents below the wilting point,where small differences in water content result in large potential energy changes.

Simulation of facet dendrite growth with strong interfacial energy anisotropy by phase field method

Numerical simulations based on a new regularized phase-field model were presented, to simulate the solidification of hexagonal close-packed materials with strong interfacial energy anisotropies. Results show that the crystal grows into facet dendrites,displaying six-fold symmetry. The size of initial crystals has an effect on the branching-off of the principal branch tip along the<100> direction, which is eliminated by setting the b/a(a and b are the semi-major and semi-minor sizes in the initial elliptical crystals, respectively) value to be less than or equal to 1. With an increase in the undercooling value, the equilibrium morphology of the crystal changes from a star-like shape to facet dendrites without side branches. The steady-state tip velocity increases exponentially when the dimensionless undercooling is below the critical value. With a further increase in the undercooling value, the equilibrium morphology of the crystal grows into a developed side-branch structure, and the steady-state tip velocity of the facet dendrites increases linearly. The facet dendrite growth has controlled diffusion and kinetics.

A New Carbon and Oxygen Balance Model Based on Ecological Service of Urban Vegetation

The application of human induced oxygen consumption and carbon emission theory in urban region was summed up and on this base a new model of urban carbon and oxygen balance (UCOB) was constructed by calculating the carbon and oxygen fluxes. The purpose was to highlight the role of vegetation in urban ecosystems and evaluate the effects of various human activities on urban annual oxygen consumption and carbon emission. Hopefully,the model would be helpful in theory to keep the regional balance of carbon and oxygen,and provide guidance and support for urban vegetation planning in the future. To test the UCOB model,the Jimei District of Xiamen City,Fujian Province,China,a very typical urban region,was selected as a case study. The results turn out that Jimei′s vegetation service in oxygen emission and carbon sequestration could not meet the demand of the urban population,and more than 31.49 times of vegetation area should be added to meet the whole oxygen consumption in Jimei while 9.60 times of vegetation area are needed to meet the carbon sequestration targets. The results show that the new UCOB model is of a great potential to be applied to quantitative planning of urban vegetation and regional eco-compensation mechanisms.

Mountain Wood vs. Lowland Wood Harvesting Methods： An Ecological Case Study

Are Austrian mountain wood harvesting techniques more ecological than techniques applied in the lowlands of southern Germany？ For this comparative study, the authors selected the area of Lower Bavaria for lowland wood, as a great deal of wood is imported from this region to western Austria. At first, the felling area is described for both regions, from forest site to sawmill. Thereby, the authors create mean values related to timber harvesting and transportation, which are applicable to the whole of western Austria and Lower Bavaria, southern Germany. Secondly, the eco-balance of mountain and lowland wood is established. It is based on the following impact categories： global warming potential, acidification potential, eutrophication potential, ozone depletion potential and non-renewable primary energy. The environmental impact is more expressive if the results are applied to a specific construction part （i.e., glued laminated timber-ceiling）. Our research study showed the eco-balance of western Austrian mountain wood is more favourable than the environmental impact of harvesting lowland wood in southern Germany.

A Deep-Ecological Reading of William Wordsworth＇s Poetry

From the 1960s, the increasingly serious ecological crisis gave rise to ecocriticism. William Wordsworth （1770-1850）, a representative of romantic poets, composes substantial poems to eulogize nature and to encourage equality and harmony between nature and human beings. From the angle of deep ecology, a branch of ecological study, this paper aims to analyze the ecological consciousness conveyed in Wordsworth＇s poetry. It analyzes the adverse impacts of industrialization on nature and man in Wordsworth＇s poetry. It elaborates further on ecological thoughts in Wordsworth＇s poetry. And finally, it summarizes how Wordsworth criticizes industrialization in his poetry and how he expresses his ecological thoughts--ecological equilibrium, social equality and harmony, and nature preservation

Decision-making Principles and Evaluation Frame of Harmonious Fiscal Policy

Harmonious fiscal policy is the Inner requirement for Constructing Harmonious society and is an important means of realiziug such society. The harmonious fiscal policy should realize the harmony of “two hands”, the harmony of values, the unity of short-term and long-term harmony the unity of parts and the whole harmony, the unity of internal and external efficacy harmony. To scientifically evaluate harmony of fiscal policy is the prerequisite to bring harmonious fiscal policy to its full play.

A study of regional CDM projects distribution in China

CDM will reduce the global GHG emissions with lower costs while promoting sustainable development of the developing countries.However,the lack of distribution equilibrium has been a problem not solved for a long time.In order to increase CDM distribution equilibrium in China,CDM support requirement extent of different areas is analyzed based on the study on the economic development and sustainable development capability.At the same time,registered and issued projects are analyzed to have an assessment on the CDM distribution equilibrium in China.Based on the study,it is concluded that there is a lack of CDM distribution equilibrium in China as most of CDM support has gone to the relatively more developed areas.Based on the reason analysis from the sector development,CDM market and information circulation aspects,suggestions are given to support CDM development in western areas by the"sector development guidance+CDM capability construction+market support"mode in this paper.

Energy Balance of Irrigated Intercropping Field in the Middle Reaches of Heihe River Basin

Based on the experiments conducted in an irrigated intercropping field in Zhangye Oasis in the middle reaches of Heihe River basin in 2004, the characteristics of radiation budget are analyzed. Furthermore, energy balance is cal- culated by using Bowen-Ratio Energy Balance (BREB) method. The results show that the ratio of the absorbed radiation to the incoming short radiation in intercropping crop canopy-soil system is increasing with growing stages, from 0.81 in the initial growing stage (IGS) to 0.86 in the late growing stage (LGS). The net radiation, which is smaller in IGS, in- creases rapidly in the first period of the middle growing stage (MGS) and reaches the maximum value in the second period of MGS. It then somewhat decreases in LGS. The ratio of net radiation to total radiation has a similar trend with the net radiation. In the whole growing stages, latent heat flux, which takes up 70% or so of the net radiation, is the dominant item in energy balance. Sensible heat flux shares 20% of the net radiation and soil heat flux has a percentage of 10%. The characteristics of heat balance vary distinctly in different growing stages. In IGS, the ratios of latent heat flux, sensible heat flux and soil heat flux to net radiation are 44.5%, 23.8% and 31.7% respectively. In MGS, with the in- creasing of latent heat flux and the decreasing of sensible heat flux and soil heat flux, the ratios turn into 84.4%, 6.3% and 9.3%. In LGS, the soil heat flux maintains 0W/m2 or so, and latent heat flux and sensible heat flux take up 61.4% and 38.6% respectively. The energy balance also shows an obvious daily variation characteristic.

Simulating Net Carbon Budget of Forest Ecosystems and Its Response to Climate Change in Northeastern China Using Improved FORCCHN

As dominant biomes,forests play an important and indispensable role in adjusting the global carbon balance under climate change.Therefore,there are scientific and political implications in investigating the carbon budget of forest ecosystems and its response to climate change.Here we synthesized the most recent research progresses on the carbon cycle in terrestrial ecosystems,and applied an individual-based forest ecosystem carbon budget model for China(FORCCHN) to simulate the dynamics of the carbon fluxes of forest ecosystems in the northeastern China.The FORCCHN model was further improved and applied through adding variables and modules of precipitation(rainfall and snowfall) interception by tree crown,understory plants and litter.The results showed that the optimized FORCCHN model had a good performance in simulating the carbon budget of forest ecosystems in the northeastern China.From 1981 to 2002,the forests played a positive role in absorbing carbon dioxide.However,the capability of forest carbon sequestration had been gradually declining during the the same period.As for the average spatial distri-bution of net carbon budget,a majority of the regions were carbon sinks.Several scattered areas in the Heilongjiang Province and the Liaoning Province were identified as carbon sources.The net carbon budget was apparently more sensitive to an increase of air temperature than change of precipitation.

Genetic Diversity of Cameroon Native Goat Populations Revealed by Caprine Microsatellites

A total of seventeen caprine microsatellite markers were used on 169 goats to investigate genetic diversity of eight Cameroon native goat populations and to assess genetic differentiation with the East African small goat. All microsatellites showed a high polymorphic content （PIC） of more than 0.5 in almost all ecotypes. These microsatellite markers were useful for native goat ecotypes variability assessment. Expected heterozygosity of all ecotypes was above 0.5, varying from 0.2 to 0.7. Only goats from Eastern rainforest ecotype deviated from Hardy-Weinberg equilibrium test （P 〉 0.001）. Although geographic distribution was a good indication of differentiation, there appeared a tendency of genetic exchange between various ecotypes in Cameroon native goats.

Studies on Material Cycling in Evergreen Broad-Leaved Forest Ecosystem in Hangzhou: Ⅰ. Precipitation Distribution

Through the long-term plot studies on the precipitation distribution in the evergreen broad-leaved forest ecosystem in Hangzhou for two years, it was indicated that the pattern of precipitation distribution included larger amounts of penetration water and stemflow and a lower amount of interception water. The results revealed that the main factors to infulence the percentages of penetration and stemflow were the air temperature and the leaf area of the forest. The quantity of seepage through the litter layer was much larger than that through the soil layers which decreased sharply with soil depth. The output of water from the ecosystem by surface runoff and deep infiltration through the soil was much lower, only being 5.20 percent of the rainfall, while the water evapotranspiration loss was as large as more than 90 percent of it. The losses by the soil evaporation and plant evapotranspiration were the largest part of output in this forest ecosystem.

Simulation and analysis for anthropogenic heat release

Heat balance of urban ecosystem is a key point for the study of urban climate and micro-climate pattern and its change mechanism. Urban heat island effect is becoming increasingly serious,which is mainly caused by the change of the earth's surface cover and the anthropogenic heat release. In this study,the simulation experiment for the anthropogenic heat release was designed according to the heat balance principle. A set of buildings of miniature city were used to constitute the residential area,U grooves were applied to simulate the single building,and the fluorescent lamps in the U groove were regarded as the heat sources of the anthropogenic heat release. The simulation experiment was launched with long-short wave sun photometer,sonic anemothermometer and heat flow gauge in the experiment site. Then the net solar radiation,sensible heat flux and heat flux into the ground were determined. The quantities of the anthropogenic heat release were calculated based on the heat balance principle,and were compared with the theoretical power consumption of the fluorescent lamps. The root mean square error( RMSE) of the simulation for the anthropogenic heat release reaches0. 078 W·m- 2,a comparatively high precision,which showes that the anthropogenic heat release can be accurately determined through the simulation experiments. This study provided a scientific method for the purpose of monitoring the anthropogenic heat release.

Temporal and Spatial Dynamics Analysis of Grassland Ecosystem Pressure in Kazakhstan

Affected by climate change and policy factors,Kazakhstan is the country with the most severe ecological degradation and grassland conflicts in Central Asia.Therefore,studying the state of grassland carrying resources in Kazakhstan is particularly important for understanding the responses of grassland ecosystems to climate change and human activities.Based on Kazakhstan's remote sensing data and animal husbandry statistics,this study analyzes the patterns of changes in grassland ecosystems in Kazakhstan based on the supply and consumption of these ecosystems.The results show that:1)From 2003 to 2017,the number of livestock raised in Kazakhstan showed a trend of sustained and steady growth.Due to freezing damage,the scale of livestock farming decreased in 2011,but a spatial difference in the livestock farming structure was not obvious.2)The fluctuation of grassland supply in Kazakhstan has increased,while the consumption due to animal husbandry has also continued to increase,resulting in an increasing pressure on the grassland carrying capacity.3)Between 2003 and 2017,the overall grassland carrying status of Kazakhstan have been abundant,but the grassland carrying pressure index has shown a steadily increasing trend,the grassland carrying pressure is growing,and it is mainly determined by grassland productivity.The greater pressure in lower Kyzylorda state,the southern Kazakhstan state of the cultivated land and the northern Kazakhstan state has gradually expanded to include the agro-pastoral zone and the semi-desert zone.

Preliminary Estimation of Soil Carbon Sequestration of China’s Forests during 1999–2008

The National Forest Inventory(NFI)is an important resource for estimating the national carbon balance(These data were unpublished data,and we could only obtain the data before 2008 through data search by now).Based on the data from sample plots,the literature,and NFI,as well as the relationships between volume,biomass,annual litterfall and soil respiration of different forest types,the net ecosystem production(NEP),changes in forest biomass carbon storage(△Cbiomass)and non-respiratory losses(NR)of China’s forests during 1999-2008 were estimated,and the forest soil carbon sequestration(△Csoil)was assessed according to the carbon balance principle of the forest ecosystem(△Csoil=NEP-NR-△Cbiomass).The results showed that the total NEP,△Cbiomass,NR and△Csoil values for China’s forests were 157.530,48.704,31.033 and 77.793 Tg C yr^(-1) respectively,and average NEP,△Cbiomass,NR,and△Csoil values were 101.247,31.303,19.945 and 49.999 g C m^(-2) yr^(-1) respectively.There were large spatial differences in forest soil carbon sequestration in different parts of China.The forest soil in Jiangxi,Hunan,Zhejiang,Fujian,Anhui,Shanxi,Shaanxi,Guangxi and Liaoning served as carbon sources and the carbon released was about 25.507 Tg C yr^(-1).The other 22 provinces served as carbon sinks and the average carbon sequestration by forest soil came to 103.300 Tg C yr^(-1).This research established a method for evaluating soil carbon sequestration by China’s forests based on the NFI,which is a useful supplement to current statistical data-based studies on the forest ecosystem carbon cycle,and can promote comparable studies on forest soil carbon sequestration with consistent research methods at the regional scale.

Effects of different gap filling methods and land surface energy balance closure on annual net ecosystem exchange in a semiarid area of China

Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange.

Impaired function of the suprachiasmatic nucleus rescues the loss of body temperature homeostasis caused by time-restricted feeding

The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The potential side effects of TRF remain unknown.Here we show that daily 4-h TRF treatment in mice can severely impair body temperature homeostasis and can result in lethality.Nearly half of the mice died at 21℃,and all mice died at 18℃during 4-h TRF.This effect was modulated by the circadian clock and was associated with severe hypothermia due to loss of body temperature homeostasis.Remarkably,disrupting the circadian clock by SCN lesions or constant light rescued lethality during TRF.Analysis of circadian gene expression in the dorsomedial hypothalamus(DMH)demonstrated that TRF reprograms rhythmic transcriptome in DMH and suppresses expression of genes,such as Ccr5 and Calcrl,which are involved in thermoregulation.Together,our results demonstrated a potent effect of TRF on body temperature homeostasis and the role of SCN function in this process.Our results further suggested that circadian arrhythmicity can have potential beneficial effects under certain stress conditions.