结构化学习:数学教育的自然样态

结构化学习,是基于教师作为专业素养发展者的研究学习,是基于学生作为自然学习者的自主学习。结构化学习,指向具有教育自然意义单元的结构内容、教育自然生命成长的结构过程与教育自主向上形态的结构目标,关注每一个具体的人的发展,是维护数学教育自然样态的创造性教育。

Characteristics and the Issue of Eco-safety for the Plant Biodiversity in Longtan Nature Reserve

The characteristic and status quo of plant biodiversity in Longtan Nature Reserve was evaluated from the three aspects of species diversity, genetic diversity and ecosystem dioversity. And the primary eco-safety influencing factors for plant biodiversity in Longtan nature reserve were put forward. The results show that the plant species in Longtan Nature Reserve was abundant, including 2 821 species of vascular bundle plants belonging to 1029 genera, 205 families. The main problems influencing eco-safety included the destruction of endangered wild plants and exotic species invasion.

Mechanical properties and energy mechanism of saturated sandstones

The effects of saturation on post-peak mechanical properties and energy features are main focal points for sandstones. To obtain these important attributes, post-peak cyclic loading and unloading tests were conducted on sandstone rock samples under natural and saturated states using the RMT-150B rock mechanics testing system. After successful processing of these tests, comparisons of stress-strain, strength, deformation, damage, and degradation of mechanical properties, wave velocity, and energy features of sandstone were conducted between natural and saturated states. The results show that saturation has evident weakening effects on uniaxial cyclic loading and unloading strength and elastic modulus of post-peak fracture sandstone. With the increase of post-peak loading and unloading period, the increases in amplitude of peak axial, lateral, and volumetric strains are all enhanced at approximately constant speed under the natural state. The increase in amplitude of axial peak strain is also enhanced at approximately constant speed, while the amplitudes of lateral and volumetric peak strains increase significantly under the saturated state. Compared with the natural state, the increase in amplitude of saturated samples＇ peak lateral and volumetric strains, and the post-peak cyclic loading and unloading period all conform to the linearly increasing relationship. Under natural and saturated states, the damage factor （the plastic shear strain） of each rock sample gradually increases with the increase of post-peak cyclic loading and unloading period, and the crack damage stress of each rock sample declines rapidly at first and tends to reach a constant value later with the increase in plastic shear strain. Under natural and saturated states, the wave velocities of rock samples all decrease in the process of post-peak cyclic loading and unloading with the increase in plastic shear strain. The wave velocities of rock samples and plastic shear strain conform to the exponential relationship with a constant. Saturation reduces the total absorption energy, dissipated energy, and elastic strain energy of rock samples.

Taxonomic Distinctness of Macrofauna as an Ecological Indicator in Laizhou Bay and Adjacent Waters

In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising.

Ecology, Biology and Biometry of an Endemic Fabaceae： Genista Saharae Cosson and Durieu

Genista saharae Cosson and Durieu, endemic Saharan Africa, is a spontaneous fabaceae dunes south of M＇sila （Algeria）. Perfectly adapted to arid and sandy soils, this species is a remarkable plant for dune fixation and thus fights against desertification. The objective of this study is to provide local species to various development programs of steppe ecological systems in nature and therefore ensure the rehabilitation of these species while considering the conservation of biodiversity and sustainable management of biological resources steppe. After a field survey and stratified sampling, the methodological approach has taken into account three types of analysis： a biometric analysis of a population of 100 individuals of this species, the second analysis on its biology at last an analysis of an ecological factor dealing with the accuracy governing the distribution of this species in Maiter Oued in the south of M＇sila. The results have clarified the ecology of this species to better understand its biology and to develop statistically a diagnosis on the phenology and morphology of various organs （pods, seeds, leaves） of Genista saharae Cosson and Durieu.

Impacts of Anthropogenic Stresses on Biodiversity： A Case Study of Lumbini, Nepal

Biodiversity conservation denotes the protection, management and utilization of resources available on or below the surface of the earth. The sustainability of biodiversity resources rely on the ecological balance. A sound planning based on ecological background and human needs provide successful management of natural resources. The study area, Lumbini harbors rich biodiversity and provide significant habitats for several species of birds, mammals, herpetofauna and fish. There are four major habitat types in Lumbini area-farmland, forest, grassland and wetland. The resources outside the Lumbini Development Trust and surrounding villages have already depleted due to excessive human interference in natural resources. Lumbini and its vicinity are rich in natural resources but poor in terms of infrastructure and delivery of services. The areas are losing natural wealth to pay for development. Rural areas around Lumbini are confronted with worsening poverty, ill health, illiteracy and continuing deterioration of natural ecosystems on which the local residents depend for their well-being. The only way to assure a safer and more prosperous future in Lumbini area is to deal with environment and development issues in a balanced manner. This research work attested that the local stakeholders feel ownership on people centered conservation.