多媒体辅助初中数学教学的“趋利”以及“避害”

伴随当前社会和科学技术的快速发展,多媒体技术在各个领域得到了广泛应用。教师逐渐意识到多媒体技术的特点,将其应用于教育领域之后,有效地提高了整体的教学质量。多媒体技术具有一定的特殊性,能够将枯燥乏味的知识变得更加有趣,在初中阶段的数学教学中,多媒体技术应用价值较高,能够实现教学模式的转变。

中国古代北方草原部族的战利品分配方式及其演进

中国古代北方草原部族的战利品分配方式有一个演进过程。匈奴鼓励个人获取战利品,拓拔鲜卑统一控制战利品并班赐,而高车、突厥、奚依然如匈奴一样由个人竞相获取。契丹、女真、蒙古以及满族建立政权之际,都确立了与拓跋鲜卑相同的政策,严格控制战利品并按原则分配。各部族的战利品分配方式反映着其政治水平,统一控制与分配战利品体现了草原部族政治水平的提高,保证了各部族所建国家的发展。

Evaluations and Suggestions about Effect of Weather in Guangxi on Rice Production

[Objective] The paper aims to study the effect of weather on rice production in Guangxi. [Method] The authors evaluated the effect of weather and weather disasters in Guangxi on rice production by comparison and analysis in terms of temperature,rain and sunlight in 2009. [Result] The study summarized the main favorable and unfavorable weather conditions of rice growth,and proposed the measures and suggestions to tend to interest and avoid harm on rice production in Guangxi. [Conclusion] This study provides references to the evaluations about effect of weather in Guangxi on rice production and suggestions on how to reduce weather disasters influence and ensure rice production security.

Observed trends in diurnal temperature range over Nigeria

The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.

Possible contribution of Arctic sea ice decline to intense warming over Siberia in June

Siberia experienced intense heat waves in 2020,and this unusual warming may have caused more wildfires and losses of permafrost than normal,both of which can be devastating to ecosystems.Based on observational data,this paper shows that there was an intense warming trend over Siberia(60°–75°N,70°–130°E)in June during 1979–2020.The linear trend of the June surface air temperature is 0.90℃/10 yr over Siberia,which is much larger than the area with the same latitudes(60°–75°N,0°–360°,trend of 0.46℃/10 yr).The warming over Siberia extends from the surface to about 300 h Pa.Increased geopotential height in the mid-to-upper troposphere plays an important role in shaping the Siberian warming,which favors more shortwave radiation reaching the surface and further heating the overlying atmosphere via upward turbulent heat flux and longwave radiation.The Siberian warming is closely related to Arctic sea-ice decline,especially the sea ice over northern Barents Sea and Kara Sea.Numerical experiments carried out using and atmospheric general circulation model(IAP-AGCM4.1)confirmed the contribution of the Arctic sea-ice decline to the Siberian warming and the related changes in circulations and surface fluxes.

Analysis on the Cy-Pres Doctrine in the Public Benefit Trust

Public benefit trust is of great significance to the development of social public welfare, and the cy-pres doctrine as a special principle of public benefit trust, plays an important role in protecting the continuation of public benefit trust, and the realization and reasonable use of high-efficiency trust properties. In this paper, therefore, the origin, establishment, and development trend of the approximation principle as well as its current legislative situation in China are studied, and also its applicability of the Cy-Pres doctrine in China＇s public benefit trust is briefly evaluated, so as to further deepen the understanding of the Cy-Pres doctrine and develop the public benefit trust undertakings in China.

Independent Auditors Report： Australian Trends From 1996 to 2010

Audit report is the primary means of communication for auditors. To reduce the phenomenon of agency conflict, auditors work as agents for shareholders and report to them after reviewing the financial statements. In last 15 years, Australia has witnessed some major changes in Australian economy which have affected Australian business and its auditors＇ opinions. This paper examines the trend of audit opinions issued to Australian listed companies during this period. In total, 20,473 audit opinions were sited over the 15-year period, i.e., from 1996 to 2010. This research found that over the period, unqualified report was the most common type of audit reports issued in Australia with an average of 96.4%. The average rate at which the Big 4 audit firms issue unqualified reports is 88% compared with 76% issued by the non-Big 4 firms. It is also evidenced that the rate at which modified reports were issued during and after global financial crisis （GFC） （2007-2009） has increased across all industries, while the most noticeable increase occurred in the financial services, materials, and industrial sectors.

Development Trends and Evaluation of Egbe Reservoir Water Nutrient Status in Ekiti State, Nigeria

A study about some physicochemical parameters of Egbe reservoir was carried out from September 2005 to December 2006. The parameters include mean temperature, pH, conductivity, alkalinity, TSS, TDS, DO and BOD which have values of 28.7±0.9 ℃ ; 8.3±0.3; 831±172.5 μS/cm; 165.4±18.3 mg/L; 0.06±0.1 mg/L; 0.4±0.6 mg/L; 7.8±2.4 mg/L and 5.2±1.6mg/L, respectively. Temperature and pH were measured in the field using mercury-in-glass thermometer calibrated in degrees Celsius and pH meter, respectively. TSS and TDS were measured by grayimetric methods, while alkalinity was measured titrimetrically and DO and BOD were measured by Winkler＇s method. For the nutrients, nitrate was measured color±metrically, phosphate by Stannous Chloride method and sulphate by turbidimetric method. Mean concentration of nitrate, phosphate, and sulphate were 15.6±8.6 rag/L; 42.5±19.4 mg/L and 72.3±14.7 mg/L respectively. Nowadays, eutrophication of natural waters is one of the most significant causes of deterioration of water quality, and nitrates and phosphates are probably the key nutrients in controlling the growth of aquatic plants. Though the mean concentration of nitrates and phosphates in the reservoir water were within the acceptable limit, yet their concentrations in some locations of reservoir were high enough to encourage the growth of aquatic macrophytes which would increase productivities. Hence, it is necessary to check their further increase, and periodic monitoring and preventive measures must be adopted to save the reservoir from eutrophication.

Spatio-temporal Patterns of Vegetation Change in Kazakhstan from 1982 to 2015

The Normalized Difference Vegetation Index（NDVI）, as a key indicator of vegetation growth, effectively provides information regarding vegetation growth status. Based on the Global Inventory Monitoring and Modeling System（GIMMS） NDVI time series data for Kazakhstan from 1982 to 2015, we analyzed the spatial pattern and changes in the vegetation growth trend. Results indicated that the three main types of vegetation in Kazakhstan are cropland, grassland and shrubland, and these are distributed from north to south. While the regional distribution pattern is obvious, the vegetation index decreased from north to south. The average NDVI values of the three main vegetation types are in the order of cropland grassland shrubland. During the period from 1982 to 2015, the NDVI initially increased（1982–1992）, then decreased（1993–2007）, and then increased again（2008–2015）. The areas where NDVI decreased significantly accounted for 24.0% of the total land area. These areas with vegetation degradation are mainly distributed in the northwest junction between cropland and grassland, and in the cropland along the southern border. The proportions of total grassland, cropland and shrubland areas that were degraded are 23.5%, 48.4% and 13.7%, respectively. Areas with improved vegetation, accounting for 11.8% of the total land area, were mainly distributed in the mid-east cropland area, and the junction between cropland and grassland in the mid-east region.